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+publicationDate,title,abstract,id
+2011-08-31,Catalytic effect of the spinel ferrite nanocrystals on the growth of carbon nanotubes,"We prepared three ferrite nanocatalysts: (i) copper ferrite (CuFe2O4), (ii)
+ferrite where cobalt was substituted by nickel (NixCo1-xFe2O4, with x= 0, 0.2,
+0.4, 0.6), and (iii) ferrite where nickel was substituted by zinc
+(ZnyNi1-yFe2O4 with y= 1, 0.7, 0.5, 0.3), by the sol-gel method. The X-ray
+diffraction patterns show that the ferrite samples have been crystallized in
+the cubic spinel structural phase. We obtained the grain size by FE-SEM images
+in the range of 10-70 nm, and their magnetic properties by VSM. Next, carbon
+nanotubes were grown on these nanocatalysts by the CCVD method. We show that
+the catalytic effects of these nanocrystals on the carbon nanotube growth
+depend on cation distributions in the octahedral and tetrahedral sites,
+structural isotropy and catalytic power due to cations. Our study can have
+applications in finding a suitable candidate of doped ferrite nanocrystals as
+catalysts for carbon nanotube growth. More interestingly, the yield of the
+fabrication of carbon nanotubes can be considered as an indirect tool to study
+catalytic activity of ferrites.",1108.6256v1
+2019-11-15,Exchange bias and training effect in an amorphous zinc ferrite/ nanocrystalline gallium ferrite bilayer thin film,"In this paper I report, exchange bias effect in a bilayer thin film of
+amorphous zinc ferrite and nanocrystalline gallium ferrite. The amorphous zinc
+ferrite layer was deposited at room temperature (Ts = RT) on top of a
+nanocrystalline gallium ferrite thin film using a pulsed laser. This bilayer
+film showed large exchange bias effect (He ~ 418 Oe at 2 K). The exchange bias
+shift decreased exponentially as the temperature increased and disappeared for
+T > 30 K. Along with the exchange bias shift the film also showed enhanced
+magnetization in Field Cooled (FC) measurements as compared to the Zero Field
+Cooled (ZFC) magnetization. The bilayer film also showed training effect at 2
+K, which followed spin configurational relaxation model. The observed exchange
+bias effect could be attributed to the pinning anisotropy of the spin glass
+amorphous zinc ferrite layer pinned at the interface of gallium ferrite.",1911.06493v1
+2004-01-29,Review on Giant Magnetoelectric effects in Oxide ferromagnetic/ferroelectric Layered Structures,"The synthesis of layered ferrite-lead titanate zirconate (PZT) and lanthanum
+nanganite-PZT and the observation of giant magneto-electric interactions are
+discussed. The ferrites used in our studies included pure and Zn substituted
+cobalt-, nickel- and lithium ferrites. Ferromagnetic manganites used included
+both calcium and strontium substituted systems. The samples were prepared from
+10-40 mm thick films obtained by tape-casting. Our studies showed strong ME
+coupling in manganite-PZT and cobalt zinc ferrite-PZT, and a giant ME effect in
+nickel zinc ferrite-PZT. We found evidence for Zn assisted enhancement in ME
+coefficients that were attributed to low anisotropy and high permeability that
+resulted in favorable magneto-mechanical coupling in the composites.",0401607v1
+2008-07-27,Magnetic-dipolar and electromagnetic vortices in quasi-2D ferrite disks,"Magnetic-dipolar-mode (MDM) oscillations in a quasi-2D ferrite disk show
+unique dynamical symmetry properties resulting in appearance of topologically
+distinct structures. Based on the magnetostatic (MS) spectral problem
+solutions, in this paper we give an evidence for eigen MS power-flow-density
+vortices in a ferrite disk. Due to these circular eigen power flows, the MDMs
+are characterized by MS energy eigen states. It becomes evident that the reason
+of stability of the vortex configurations in saturated ferrite samples is
+completely different from the nature of stability in magnetically soft
+cylindrical dots. We found a clear correspondence between analytically derived
+MDM vortex states and numerically modeled electromagnetic vortices in quasi-2D
+ferrite disks.",0807.4281v1
+2004-08-31,Handedness of magnetic-dipolar modes in ferrite disks,"For magnetic-dipolar modes in a ferrite, components of the magnetic flux
+density in a helical coordinate system are dependent on both an orientation of
+a gyration vector and a sign of a pitch. It gives four types of helical
+harmonics for magnetostatic-potential wave functions in a ferrite disk. Because
+of the reflection symmetry breaking, coupling between certain types of helical
+harmonics takes place in the reflection points. The reflection feature leads to
+exhibition of two types of resonances: the ""right"" and ""left"" resonances. These
+resonances become coupled for a ferrite disk placed in a homogeneous tangential
+RF magnetic field. One also observes such resonance coupling for a ferrite disk
+with a symmetrically oriented linear surface electrode, when this ferrite
+particle is placed in a homogeneous tangential RF electric field. In a
+cylindrical coordinate system handedness of magnetic-dipolar modes in a ferrite
+disk is described by spinor wave functions.",0408682v2
+2010-06-01,Magnetic and humidity sensing properties of nanostructured Cu[x]Co[1-x]Fe2O4 synthesized by auto combustion technique,"Magnetic nanomaterials (23-43 nm) of Cu$_x$Co$_{1-x}$Fe$_2$O$_4$\ (x = 0.0,
+0.5 and 1.0) were synthesized by auto combustion method. The crystallite sizes
+of these materials were calculated from X-ray diffraction peaks. The band
+observed in Fourier transform infrared spectrum near 575 cm$^{-1}$ in these
+samples confirm the presence of ferrite phase. Conductivity measurement shows
+the thermal hysteresis and demonstrates the knee points at 475$^o$C, 525$^o$C
+and 500$^o$C for copper ferrite, cobalt ferrite and copper-cobalt mixed ferrite
+respectively. The hystersis M-H loops for these materials were traced using the
+Vibrating Sample Magnetometer (VSM) and indicate a significant increase in the
+saturation magnetization (M$_s$) and remanence (M$_r$) due to the substitution
+of Cu$^{2+}$ ions in cobalt ferrite, while the intrinsic coercivity (H$_c$) was
+decreasing. Among these ferrites, copper ferrite exhibits highest sensitivity
+for humidity.",1006.0083v1
+2012-09-20,Nucleating Acicular Ferrite with Galaxite (Al2O3MnO) and Manganese Oxide (MnO2) in FeMnAlC steels,"Effectiveness of galaxite (Al2O3MnO) and manganese oxide (MnO2) in nucleating
+acicular ferrite was demonstrated in a steel with composition of
+Fe-13.92Mn-4.53Al-1.28Si-0.11C. The hot rolled and quenched steel had a duplex
+microstructure of delta-ferrite and partially transformed austenite. Thermal
+treatments were used to manipulate the concentration and type of oxides and the
+ferrite plate density was found to correlate with inclusions of low misfit.
+Both bainitic and acicular ferrite were observed and the prior austenite had a
+grain diameter of 16.5 micrometers. Upon tensile testing the retained austenite
+transformed to alpha-martensite. Ultimate tensile strength and elongation were
+970 MPa and 40 percent. The yield strength was found to be dependent on the
+ferrite plate size, which varied linearly with the strength of the austenite.
+Ductility decreased as the strength disparity between delta-ferrite and
+deformation-induced alpha-martensite increased.",1209.4546v1
+2021-04-23,"Plasticity, localization, and damage in ferritic-pearlitic steel studied by nanoscale digital image correlation","The evolution of deformation from plasticity to localization to damage is
+investigated in ferritic-pearlitic steel through nanometer-resolution
+microstructure-correlated SEM-DIC (u-DIC) strain mapping, enabled through
+highly accurate microstructure-to-strain alignment. We reveal the key
+plasticity mechanisms in ferrite and pearlite as well as their evolution into
+localization and damage and their relation to the microstructural arrangement.
+Notably, two contrasting mechanisms were identified that control whether damage
+initiation in pearlite occurs and, through connection of localization hotspots
+in ferrite grains, potentially results in macroscale fracture: (i) cracking of
+pearlite bridges with relatively clean lamellar structure by brittle fracture
+of cementite lamellae due to build-up of strain concentrations in nearby
+ferrite, versus (ii) large plasticity without damage in pearlite bridges with a
+more ""open"", chaotic pearlite morphology, which enables plastic percolation
+paths in the interlamellar ferrite channels. Based on these insights,
+recommendations for damage resistant ferritic-pearlitic steels are proposed.",2104.11817v2
+2022-05-13,Ferrite: A Judgmental Embedding of Session Types in Rust,"\emph{Session types} have proved viable in expressing and verifying the
+protocols of message-passing systems. While message passing is a dominant
+concurrency paradigm in practice, real world software is written without
+session types. A limitation of existing session type libraries in mainstream
+languages is their restriction to linear session types, precluding application
+scenarios that demand sharing and thus aliasing of channel references.
+  This paper introduces Ferrite, a shallow embedding of session types in Rust
+that supports both \emph{linear} and \emph{shared} sessions. The formal
+foundation of Ferrite constitutes the shared session type calculus $\sills$,
+which Ferrite encodes via a novel \emph{judgmental embedding} technique. The
+fulcrum of the embedding is the notion of a typing judgment that allows
+reasoning about shared and linear resources to type a session. Typing rules are
+then encoded as functions over judgments, with a valid typing derivation
+manifesting as a well-typed Rust program. This Rust program generated by
+Ferrite serves as a \emph{certificate}, ensuring that the application will
+proceed according to the protocol defined by the session type. The paper
+details the features and implementation of Ferrite and includes a case study on
+implementing Servo's canvas component in Ferrite.",2205.06921v2
+2016-06-08,Magnetoelectric effect in layered ferrite/PZT composites. Study of the demagnetizing effect on the magnetoelectric behavior,"We report the use of high magnetomechanical coupling ferrites in
+magnetoelectric (ME) layered composites. Bilayer samples combining $(Ni_{0.973}
+Co_{0.027})_{1-x} Zn_x Fe_2 O_4$ ferrites ($x = 0-0.5$) synthesized by non
+conventional reactive Spark Plasma Sintering and commercial lead zirconate
+titanate (PZT) were characterized in term of ME voltage coefficients measured
+at sub-resonant frequency. Strong ME effects are obtained and we show that an
+annealing at 1000$^\circ$C and a quenching in air improve the piezomagnetic
+behavior of Zn-rich compositions. A theoretical model that predicts the ME
+behavior was developed, focusing our work on the demagnetizing effects in the
+transversal mode as well as the longitudinal mode. The model shows that: (i)
+high ME coefficients are obtained when ferrites with high magnetomechanical
+coupling are used in bilayer ME composites, (ii) the ME behavior in transversal
+and longitudinal modes is quite similar, and differences in the shapes of the
+ME curves are mainly due the demagnetizing effects, (iii) in the transversal
+mode, the magnetic field penetration depends on the ferrite layer thickness and
+the ME coefficient is affected accordingly. The two later points are confirmed
+by measurements on ME samples and calculations. Performances of the ME
+composites made with high magnetomechanical coupling ferrites are compared to
+those obtained using Terfenol-D materials in the same conditions of size,
+shape, and volume ratio. It appears that a ferrite with an optimized
+composition has performances comparable to those obtained with Terfenol-D
+material. Nevertheless, the fabrication processes of ferrites are quite
+simpler. Finally, a ferrite/PZT based ME composite was used as a current
+sensor.",1606.02473v1
+2006-02-19,Low sintering temperature of Mg-Cu-Zn ferrites prepared by the citrate precursor method,"Mg-Cu-Zn ferrite was prepared through a wet synthetic method by a
+self-combustion reaction directly from a citrate precursor. The as-synthesized
+powders were sintered at for only 2h. XRD patterns and FTIR spectra confirm the
+formation of single phase Mg-Cu-Zn ferrite after combustion. To the best of our
+knowledge, this is the first time that Mg-Cu-Zn ferrite is sintered at such low
+temperature. The sintering process increased the crystallinity of the solid and
+the domain sizes.",0602129v1
+2007-04-19,Classical Heisenberg Hamiltonian Solution of Oriented Spinel Ferrimagnetic Thin Films,"The classical Heisenberg Hamiltonian was solved for oriented spinel thin and
+thick cubic ferrites. The dipole matrix of complicated cubic cell could be
+simplified into the form of dipole Matrix of simple cubic cells. This study was
+confined only to the highly oriented thin films of ferrite. The variation of
+total energy of Nickel ferrite thin films with angle and number of layers was
+investigated. Also the change of energy with stress induced anisotropy for
+Nickel ferrite films with N=5 and 1000 has been studied. Films with the
+magnetic moments ratio 1.86 can be easily oriented in 90 direction when N is
+greater than 400.",0704.2456v1
+2016-07-08,Third Order Perturbed Energy of Cobalt Ferrite Thick Films,"Magnetic properties and easy axis orientation of cobalt ferrite films with
+applied magnetic field and number of layers were studied. According to our
+theoretical studies explained in this manuscript, the magnetically easy and
+hard directions of cobalt ferrite films solely depend on in plane and out of
+plane magnetic fields. According to 3-D and 2-D plots, there are many easy and
+hard directions at one particular value of in plane or out of plane magnetic
+field. The magnetic properties were investigated for cobalt ferrite films with
+thickness up to 10,000 unit cells. The total magnetic energy was calculated for
+a unit spin of cobalt.",1607.02323v1
+2012-01-05,Ferrite cavities,"Ferrite cavities are used in synchrotrons and storage rings if the maximum RF
+frequency is in the order of a few MHz. We present a simple model for
+describing ferrite cavities. The most important parameters are defined, and the
+material properties are discussed. Several practical aspects are summarized,
+and the GSI SIS18 ferrite cavity is presented as an example.",1201.1154v1
+2023-01-03,Crystal Nucleation Modeling of Solvent Molecules Influence on Radius and Morphology of Nano Copper Ferrite Particles,"Nanometer copper ferrite, as a kind of nanometer particle with catalytic
+activity, and its photothermal and magnetothermal effects as ferrite, can be
+widely used in different fields. It is a general way to obtain the nano effect
+of the target by controlling the particle size. In this paper, the
+crystallization process of hydrothermal/solvothermal synthesis was analyzed,
+and the nucleation model was established to simulate the effects of solvent,
+reaction temperature and cooling time on the particle size of copper ferrite
+nanoparticles. Through Monte Carlo method and energy function, the ratio of
+nano particle agglomeration was established, and the influence of different
+reaction conditions on it was discussed.",2301.00905v1
+2018-03-25,Analytical modeling of demagnetizing effect in magnetoelectric ferrite/PZT/ferrite trilayers taking into account a mechanical coupling,"In this paper, we investigate the demagnetizing effect in ferrite/PZT/ferrite
+magnetoelectric (ME) trilayer composites consisting of commercial PZT discs
+bonded by epoxy layers to Ni-Co-Zn ferrite discs made by a reactive Spark
+Plasma Sintering (SPS) technique. ME voltage coefficients (transversal mode)
+were measured on ferrite/PZT/ferrite trilayer ME samples with different
+thicknesses or phase volume ratio in order to highlight the influence of the
+magnetic field penetration governed by these geometrical parameters.
+Experimental ME coefficients and voltages were compared to analytical
+calculations using a quasi-static model. Theoretical demagnetizing factors of
+two magnetic discs that interact together in parallel magnetic structures were
+derived from an analytical calculation based on a superposition method. These
+factors were introduced in ME voltage calculations which take account of the
+demagnetizing effect. To fit the experimental results, a mechanical coupling
+factor was also introduced in the theoretical formula. This reflects the
+differential strain that exists in the ferrite and PZT layers due to shear
+effects near the edge of the ME samples and within the bonding epoxy layers.
+From this study, an optimization in magnitude of the ME voltage is obtained.
+Lastly, an analytical calculation of demagnetizing effect was conducted for
+layered ME composites containing higher numbers of alternated layers (). The
+advantage of such a structure is then discussed.",1803.09315v1
+2022-02-16,Unusual ferrimagnetic ground state in rhenium ferrite,"Through comprehensive density functional calculations, we predict the
+stability of a rhenium-based ferrite",2202.08115v1
+2016-06-08,A method to decrease the harmonic distortion in Mn-Zn ferrite/PZT and Ni-Zn ferrite/PZT layered composite rings exhibiting high magnetoelectric effects,"We have investigated the magnetoelectric (ME) effect in layered composite
+rings subjected to circumferential AC magnetic fields and DC magnetic fields in
+radial, axial or circumferential directions. Bilayer samples were obtained
+combining different grades of commercial Mn-Zn ferrites or Ni-Zn ferrites with
+commercial lead zirconate titanate (PZT). Mn-Zn ferrites with low
+magnetostriction saturation () and low magneto-crystalline anisotropy constants
+show high ME capabilities when associated with PZT in ring structures. In
+certain conditions, these ME effects are higher than those obtained with
+Terfenol-D/PZT composites in the same layered ring structure. Magnetostrictive
+and mechanical characterizations have given results that explain these high ME
+performances. Nevertheless, Mn-Zn ferrite/PZT composites exhibit voltages
+responses with low linearity especially at high signal level. Based on the
+particular structure of the ME device, a method to decrease the nonlinear
+harmonic distortion of the ME voltages is proposed. Harmonic distortion
+analysis of ME voltages measured in different configurations allows us to
+explain the phenomenon.",1606.02469v1
+2013-09-11,Fano resonances of microwave structures with embedded magneto-dipolar quantum dots,"Long range dipole-dipole correlation in a ferromagnetic sample can be treated
+in terms of collective excitations of the system as a whole. Ferrite samples
+with linear dimensions smaller than the dephasing length, but still much larger
+than the exchange-interaction scales are mesoscopic structures. Recently, it
+was shown that mesoscopic quasi-2D ferrite disks, distinguishing by
+multiresonance magneto-dipolar-mode (MDM) spectra, demonstrate unique
+properties of artificial atomic structures: energy eigenstates, eigen
+power-flow vortices and eigen helicity parameters. Because of these properties,
+MDMs in a ferrite disk enable the confinement of microwave radiation to
+subwavelength scales. In microwave structures with embedded MDM ferrite
+samples, one can observe quantized fields with topologically distinctive
+characteristics. The use of a quasi-2D ferrite-disk scatterer with internal MDM
+resonance spectra along the channel propagation direction could change the
+transmission dramatically. In this paper, we show that interaction of the MDM
+ferrite particle with its environment has a deep analogy with the
+Fano-resonance interference observed in natural and artificial atomic
+structures. We characterize the observed effect as Fano-resonance interference
+in MDM quantum dots.",1309.2792v1
+2020-09-28,Ferrite: A Judgmental Embedding of Session Types in Rust,"This paper introduces Ferrite, a shallow embedding of session types in Rust.
+In contrast to existing session type libraries and embeddings for mainstream
+languages, Ferrite not only supports linear session types but also shared
+session types. Shared session types allow sharing (aliasing) of channels while
+preserving session fidelity (preservation) using type modalities for acquiring
+and releasing sessions. Ferrite adopts a propositions as types approach and
+encodes typing derivations as Rust functions, with the proof of successful
+type-checking manifesting as a Rust program. We provide an evaluation of
+Ferrite using Servo as a practical example, and demonstrate how safe
+communication can be achieved in the canvas component using Ferrite.",2009.13619v6
+2023-04-20,Control of conductivity in Fe-rich cobalt-ferrite thin films with perpendicular magnetic anisotropy,"We fabricated two types of cobalt-ferrite (001) thin films, insulative
+Fe-rich cobalt-ferrite CoxFe3-xO4+{\delta} (I-CFO) and conductive Fe-rich
+cobalt-ferrite CoyFe3-yO4 (C-CFO), with perpendicular magnetic anisotropy (PMA)
+on MgO (001) substrates. Although the stoichiometric cobalt-ferrite is known as
+an insulating material, it is found that the conductivity of Fe-rich
+cobalt-ferrites can be controlled by changing the source materials and
+deposition conditions in the pulsed laser deposition technique. The I-CFO and
+C-CFO films exhibit PMA through the in-plane lattice distortion. We
+investigated the Fe-ion-specific valence states in both I-CFO and C-CFO films
+by M\""ossbauer spectroscopy and X-ray magnetic circular dichroism, and found
+that the difference in conductivity corresponds to the abundance ratio of Fe2+
+state at the octahedral B-site (Oh) in the inverse spinel structure.
+Furthermore, first-principles calculations reproduce the changes in the density
+of states at the Fermi level depending on the cation vacancies at the B-site,
+which explains the difference in the conductivity between I-CFO and C-CFO.",2304.10048v1
+2023-09-24,Greener processing of SrFe$_{12}$O$_{19}$ ceramic permanent magnets by two-step sintering,"With an annual production amounting to 800 kilotons, ferrite magnets
+constitute the largest family of permanent magnets in volume, a demand that
+will only increase as a consequence of the rare-earth crisis. With the global
+goal of building a climate-resilient future, strategies towards a greener
+manufacturing of ferrite magnets are of great interest. A new ceramic
+processing route for obtaining dense Sr-ferrite sintered magnets is presented
+here. Instead of the usual sintering process employed nowadays in ferrite
+magnet manufacturing that demands long dwell times, a shorter two-step
+sintering is designed to densify the ferrite ceramics. As a result of these
+processes, dense SrFe$_{12}$O$_{19}$ ceramic magnets with properties comparable
+to state-of-the-art ferrite magnets are obtained. In particular, the
+SrFe$_{12}$O$_{19}$ magnet containing 0.2% PVA and 0.6% wt SiO$_2$ reaches a
+coercivity of 164 kA/m along with a 93% relative density. A reduction of 31% in
+energy consumption is achieved in the thermal treatment with respect to
+conventional sintering, which could lead to energy savings for the industry of
+the order of 7.109 kWh per year.",2309.15860v1
+2004-01-30,Magnetoelectric Effects in Ferromagnetic/Piezoelectric Multilayer Composites,"The observation of strong magnetoelectric effects is reported in thick film
+bilayers and multilayers of ferrite-lead titanate zirconate (PZT) and lanthanum
+nanganite-PZT. The ferrites used in our studies included pure and zinc
+substituted cobalt-, nickel- and lithium ferrites. Samples were prepared by
+sintering 10-40 mm thick films obtained by tape-casting. Measurements of ME
+voltage coefficients at 10-1000 Hz indicated a giant ME effect in nickel
+ferrite-PZT, but a relatively weak coupling in other ferrite-PZT and
+manganite-PZT systems. Multilayers prepared by hot pressing was found to show a
+higher ME coefficient than sintered samples. Evidence was found for enhancement
+in ME coefficients when Zn was substituted in ferrites. The Zn-assisted
+increase was attributed to low anisotropy and high permeability that resulted
+in favorable magneto-mechanical coupling in the composites. We analyzed the
+data in terms of our recent comprehensive theory that takes into account actual
+interface conditions by introducing an interface coupling parameter.
+Theoretical longitudinal and transverse ME voltage coefficients for unclamped
+and clamped samples are in general agreement with data. From the analysis we
+inferred excellent interface coupling for nickel zinc ferrite-PZT and weak
+coupling for other layered systems.",0401641v1
+2013-02-19,On the evolution of the non exchange spring behaviour to the exchange spring behaviour: A First Order Reversal Curve Analysis,"The magnetization behaviour of the soft Cobalt Ferrite-hard Strontium Ferrite
+nanocomposite is tuned from the non exchange spring nature to the exchange
+spring nature, by controlling the particle size of the soft Cobalt Ferrite in
+the Cobalt Ferrite: Strontium Ferrite (1:8) nanocomposite. The relative
+strength of the interaction governing the magnetization process in the
+nanocomposites is investigated using Henkel plot and First Order Reversal Curve
+(FORC) method. The FORC method has been utilized to understand the
+magnetization reversal behaviour as well as the extent of the irreversible
+magnetization present in both the nanocomposites having smaller and larger
+particle size of the Cobalt Ferrite. The magnetization process is primarily
+controlled by the domain wall movement in the nanocomposites. Using the FORC
+distribution in the (Ha, Hb) co-ordinate, the onset of the nucleation field,
+invasion of the domain wall from the soft to the hard phase, domain wall
+annihilation and the presence of the reversible magnetization with the applied
+reversal field for both the nanocomposites has been investigated. It has been
+found that for the composite having lower particle size of the soft phase shows
+a single switching behaviour corresponding to the coherent reversal of the both
+soft and hard phases. However, the composite having higher Cobalt Ferrite
+particle size shows two peak behaviour in the FORC distribution resembling
+individual switching of the soft and hard phases. The FORC distribution in (Hu,
+Hc) co-ordinate and the Henkel measurement confirms the dominant exchange
+interaction in the nanocomposites exhibiting exchange spring behaviour where as
+the occurrence of both the dipolar and exchange interaction is substantiated
+for the non exchange coupled nanocomposite.",1302.4602v1
+2010-05-18,Micromagnetic simulations of spinel ferrite particles,"This paper presents the results of simulations of the magnetization field
+{\it ac} response (at $2$ to $12$ GHz) of various submicron ferrite particles
+(cylindrical dots). The ferrites in the present simulations have the spinel
+structure, expressed here by M$_{1-n}$Zn$_{n}$Fe$_2$O$_4$ (where M stands for a
+divalent metal), and the parameters chosen were the following: (a) for $n=0$: M
+= \{ Fe, Mn, Co, Ni, Mg, Cu \}; (b) for $n=0.1$: M = \{ Fe, Mg \} (mixed
+ferrites). These runs represent full 3D micromagnetic (one-particle) ferrite
+simulations. We find evidences of confined spin waves in all simulations, as
+well as a complex behavior nearby the main resonance peak in the case of the M
+= \{ Mg, Cu \} ferrites. A comparison of the $n=0$ and $n=0.1$ cases for fixed
+M reveals a significant change in the spectra in M = Mg ferrites, but only a
+minor change in the M = Fe case. An additional larger scale simulation of a $3$
+by $3$ particle array was performed using similar conditions of the Fe$_3$O$_4$
+(magnetite; $n=0$, M = Fe) one-particle simulation. We find that the main
+resonance peak of the Fe$_3$O$_4$ one-particle simulation is disfigured in the
+corresponding 3 by 3 particle simulation, indicating the extent to which
+dipolar interactions are able to affect the main resonance peak in that
+magnetic compound.",1005.3169v1
+2003-07-13,"Structural and magnetoelectric properties of MFe2O4-PZT (M=Ni,Co) and (La)x(Ca,Sr)1-x - PZT multilayers","Thick film layered magnetoelectric composites consisting of ferromagnetic and
+ferroelectric phases have been synthesized with nickel ferrite (NFO), cobalt
+ferrite (CFO), La0.7Sr0.3MnO3 (LSMO), or La0.7Ca0.3MnO3 (LCMO) and lead
+zirconate titanate (PZT). Structural, magnetic and ferromagnetic resonance
+characterization shows evidence for defect free ferrites, but deterioration of
+manganite parameters. The resistivity and dielectric constants are smaller than
+expected values. The magnetoelectric effect (ME) is stronger in ferrite-PZT
+than in manganite-PZT. The ME voltage coefficient aE at room temperature is the
+highest in NFO-PZT and the smallest for LCMO-PZT. The transverse ME effect is
+an order of magnitude stronger than the longitudinal effect. The magnitude of
+aE correlates well with magnetic permeability for the ferrites.",0307309v1
+2004-09-22,Interaction of magnetic-dipolar modes with microwave-cavity electromagnetic fields,"We discuss the problem of magnetic-dipolar oscillations combined with
+microwave resonators. The energy density of magnetic-dipolar or magnetostatic
+(MS) oscillations in ferrite resonators is not the electromagnetic-wave density
+of the energy and not the exchange energy density as well. This fact reveals
+very special behaviors of the geometrical effects. Compared to other
+geometries, thin-film ferrite disk resonators exhibit very unique interactions
+of MS oscillations with the cavity electromagnetic fields. MS modes in a flat
+ferrite disk are characterized by a complete discrete spectrum of energy
+levels. The staircase demagnetization energy in thin-film ferrite disks may
+appear as noticeable resonant absorption of electromagnetic radiation. Our
+experiments show how the environment may cause decoherence for magnetic
+oscillations. Another noticeable fact is experimental evidence for
+eigen-electric-moment oscillations in a ferrite disk resonator.",0409583v2
+2011-03-25,Temperature dependence of core loss in cobalt substituted Ni-Zn-Cu ferrites,"The temperature dependence of core loss in cobalt substituted Ni-Zn-Cu
+ferrites was investigated. Co2+ ions are known to lead to a compensation of the
+magneto-crystalline anisotropy in Ni-Zn ferrites, at a temperature depending on
+the cobalt content and the Ni/Zn ratio. We observed similar behaviour in
+Ni-Zn-Cu and it was found that the core loss goes through a minimum around this
+magneto-crystalline anisotropy compensation. Moreover, the anisotropy induced
+by the cobalt allowed a strong decrease of core loss, a ferrite having a core
+loss of 350 mW/cm3 at 80 ^\circ C was then developed (measured at 1.5 MHz and
+25 mT). This result represents an improvement of a factor 4 compared to the
+state of art Ni-Zn ferrites.",1103.5021v1
+2011-05-30,Dependence of microwave absorption properties on ferrite volume fraction in MnZn ferrite/rubber radar absorbing materials,"We report the analysis of measurements of the complex magnetic permeability
+($\mu_r$) and dielectric permittivity ($\epsilon_r$) spectra of a rubber radar
+absorbing material (RAM) with various MnZn ferrite volume fractions. The
+transmission/reflection measurements were carried out in a vector network
+analyzer. Optimum conditions for the maximum microwave absorption were
+determined by substituting the complex permeability and permittivity in the
+impedance matching equation. Both the MnZn ferrite content and the RAM
+thickness effects on the microwave absorption properties, in the frequency
+range of 2 to 18 GHz, were evaluated. The results show that the complex
+permeability and permittivity spectra of the RAM increase directly with the
+ferrite volume fraction. Reflection loss calculations by the impedance matching
+degree (reflection coefficient) show the dependence of this parameter on both
+thickness and composition of RAM.",1105.5969v1
+2015-10-20,Reflecting (on) the Nucleation Curve: Negative Surface Energy Stabilizes Nickel Ferrite Nano-Particles in Nuclear Reactor Coolant,"We used a thermodynamics-informed first principles scheme, to calculate the
+temperature-dependent surface energies of nickel oxide (NiO) and nickel ferrite
+(NiFe2O4), two compounds that are known to deposit on the fuel rods in nuclear
+pressurized water reactors (PWR). These calculations predict a negative surface
+free energy for nickel ferrite when formed from ions in solution under PWR
+conditions of temperature, pressure and species concentration. Under these
+conditions the thermodynamics of bulk nickel ferrite yields a positive change
+in free energy for formation of the solid from dissolved ions. These results
+and their analysis in terms of classical nucleation theory have suggested a new
+fundamental relation - the reflected nucleation curve - that reveals a
+previously unrecognized aspect of the theory of phase stability. These
+calculations also suggest the presence of stable octahedral nickel ferrite
+clusters in PWR coolant that would not be observed in the coolant outside of
+service conditions, and that are not removed by the combination of filtration
+and capture of solvated ions currently used to purify the PWR coolant.",1510.05901v1
+2016-06-27,Structural and electrical properties of Sn substituted double sintering derived Ni-Zn ferrite,"The Sn substituted Ni-Zn ferrites were synthesized by the standard double
+sintering technique using nano powders of nickel oxide (NiO), zinc oxide (ZnO),
+iron oxide (Fe2O3) and tin oxide (SnO2). The structural and electrical
+properties have been investigated by the X-ray diffraction, scanning electron
+microscopy, DC resistivity and dielectric measurements. Extra intermediate
+phase has been detected along with the inverse cubic spinel phase of Ni-Zn
+ferrite. Enhancement of grain size is observed in Sn substituted Ni-Zn
+ferrites. DC resistivity as a function of temperature has been investigated by
+two probe method. The DC resistivity was found to decrease whereas the
+dielectric constants increase with increasing Sn content in Ni-Zn ferrites. The
+dielectric constant of the as prepared samples is high enough to use these
+materials in miniaturized memory devices based capacitive components or energy
+storage principles.",1606.08118v1
+2016-09-27,A Noninvasive Magnetic Stimulator Utilizing Secondary Ferrite Cores and Resonant Structures for Field Enhancement,"In this paper, secondary ferrite cores and resonant structures have been used
+for field enhancement. The tissue was placed between the double square source
+coil and the secondary ferrite core. Resonant coils were added which aided in
+modulating the electric field in the tissue. The field distribution in the
+tissue was measured using electromagnetic simulations and ex-vivo measurements
+with tissue. Calculations involve the use of finite element analysis (Ansoft
+HFSS) to represent the electrical properties of the physical structure. The
+setup was compared to a conventional design in which the secondary ferrite
+cores were absent. It was found that the induced electric field could be
+increased by 122%, when ferrite cores were placed below the tissue at 450 kHz
+source frequency. The induced electric field was found to be localized in the
+tissue, verified using ex-vivo experiments. This preliminary study maybe
+further extended to establish the verified proposed concept with different
+complicated body parts modelled using the software and in-vivo experiments as
+required to obtain the desired induced field.",1609.08333v1
+2020-11-30,Significant enhancement of magnetic shielding effect by using the composite metamaterial composed of mu-near-zero media and ferrite,"The magnetic shield plays an important role in magnetic near-field control.
+However, the requirements of efficient, ultrathin, lightweight and cheap are
+still the challenges. Here, we firstly propose a composite metamaterial in
+which the mu-near-zero media is covered with a ferrite slab. We verify that
+this structure can enhance the shielding effectiveness in a small area.
+Furthermore, we optimize the magnetic path by changing the bulk ferrite slab
+into a patterned slab. In this way, significant shielding effectiveness
+enhancement can be achieved in a large area. Experimental results show that the
+maximum shielding effectiveness (SE) of the composite metamaterial with a
+patterned ferrite is 20.56 dB, which is nearly 19 dB higher than that of a
+single ferrite slab with the same thickness of the composite metamaterial. The
+results on the composite metamaterial would be very useful in the applications
+involving magnetic shielding.",2012.07524v1
+2019-01-30,Tuning the Magnetic Ordering Temperature of Hexagonal Ferrites by Structural Distortion Control,"To tune the magnetic properties of hexagonal ferrites, a family of
+magnetoelectric multiferroic materials, by atomic-scale structural engineering,
+we studied the effect of structural distortion on the magnetic ordering
+temperature (TN). Using the symmetry analysis, we show that unlike most
+antiferromagnetic rare-earth transition-metal perovskites, a larger structural
+distortion leads to a higher TN in hexagonal ferrites and manganites, because
+the K3 structural distortion induces the three-dimensional magnetic ordering,
+which is forbidden in the undistorted structure by symmetry. We also revealed a
+near-linear relation between TN and the tolerance factor and a power-law
+relation between TN and the K3 distortion amplitude. Following the analysis, a
+record-high TN (185 K) among hexagonal ferrites was predicted in hexagonal
+ScFeO3 and experimentally verified in epitaxially stabilized films. These
+results add to the paradigm of spin-lattice coupling in antiferromagnetic
+oxides and suggests further tunability of hexagonal ferrites if more lattice
+distortion can be achieved.",1901.11118v1
+2019-08-23,Damping enhancement in coherent ferrite/insulating-paramagnet bilayers,"High-quality epitaxial ferrites, such as low-damping MgAl-ferrite (MAFO), are
+promising nanoscale building blocks for all-oxide heterostructures driven by
+pure spin current. However, the impact of oxide interfaces on spin dynamics in
+such heterostructures remains an open question. Here, we investigate the spin
+dynamics and chemical and magnetic depth profiles of 15-nm-thick MAFO
+coherently interfaced with an isostructural $\approx$1-8-nm-thick overlayer of
+paramagnetic CoCr$_2$O$_4$ (CCO) as an all-oxide model system. Compared to MAFO
+without an overlayer, effective Gilbert damping in MAFO/CCO is enhanced by a
+factor of $>$3, irrespective of the CCO overlayer thickness. We attribute this
+damping enhancement to spin scattering at the $\sim$1-nm-thick chemically
+disordered layer at the MAFO/CCO interface, rather than spin pumping or
+proximity-induced magnetism. Our results indicate that damping in ferrite-based
+heterostructures is strongly influenced by interfacial chemical disorder, even
+if the thickness of the disordered layer is a small fraction of the ferrite
+thickness.",1908.08629v2
+2003-03-10,Energy Spectra of Magnetostatic Oscillations in Ferrite Disk Resonators,"Ferromagnetic resonators with short-wavelength, so-called magnetostatic (MS),
+oscillations can be considered in microwaves as point (with respect to the
+external electromagnetic fields) particles. It was shown recently [E. O.
+Kamenetskii, Phys. Rev. E, 63, 066612 (2001)] that MS oscillations in a small
+ferrite disk resonator can be characterized by a discrete spectrum of energy
+levels. This fact allows analyzing the MS oscillations similarly to quantum
+mechanical problems. In this paper we give the results of energy spectrum
+calculations for MS oscillations in a ferrite disk resonator.",0303164v2
+2004-04-03,Electromagnetic analog of Rashba spin-orbit interaction in wave guides filled with ferrite,"We consider infinitely long electromagnetic wave guide filled with a ferrite.
+The wave guide has arbitrary but constant cross-section $. We show that Maxwell
+equations are equivalent to the Schr\""odinger equation for single electron in
+the two-dimensional quantum dot of the form D with account of the Rashba
+spin-orbit interaction. The spin-orbit constant is determining by components of
+magnetic permeability of the ferrite. The upper component of electron spinor
+function corresponds to the z-th component electric field, while the down
+component $\chi$ related to the z-th component of magnetic field by relation
+(30).",0404072v1
+2007-02-02,Induced Time-Reversal Symmetry Breaking Observed in Microwave Billiards,"Using reciprocity, we investigate the breaking of time-reversal (T) symmetry
+due to a ferrite embedded in a flat microwave billiard. Transmission spectra of
+isolated single resonances are not sensitive to T-violation whereas those of
+pairs of nearly degenerate resonances do depend on the direction of time. For
+their theoretical description a scattering matrix model from nuclear physics is
+used. The T-violating matrix elements of the effective Hamiltonian for the
+microwave billiard with the embedded ferrite are determined experimentally as
+functions of the magnetization of the ferrite.",0702041v1
+2007-08-20,Eigen electric moments of magnetic-dipolar modes in quasi-2D ferrite disk particles,"A property associated with a vortex structure becomes evident from an
+analysis of confinement phenomena of magnetic oscillations in a quasi-2D
+ferrite disk with a dominating role of magnetic-dipolar
+(non-exchange-interaction) spectra. The vortices are guaranteed by the chiral
+edge states of magnetic-dipolar modes which result in appearance of eigen
+electric moments oriented normally to the disk plane. Due to the
+eigen-electric-moment properties, a ferrite disk placed in a microwave cavity
+is strongly affected by the cavity RF electric field with a clear evidence for
+multi-resonance oscillations. For different cavity parameters, one may observe
+the ""resonance absorption"" and ""resonance repulsion"" behaviors.",0708.2678v1
+2008-05-05,Magnetoelectric oscillations in quasi-2D ferrite disk particles,"In this paper we show that magnetic-dipolar-mode (MDM) oscillations of a
+quasi-2D ferrite disk are characterized by unique symmetry features with
+topological phases resulting in appearance of the magnetoelectric (ME)
+properties. The entire ferrite disk can be characterized as a pair of two,
+electric and magnetic, coupled eigen moments. However, there is no a ""glued
+pair"" of two dipoles. An external electromagnetic field in the near-field
+region ""views"" such a ME particle, as a system with a normally oriented eigen
+electric moment and an in-plane rotating eigen magnetic dipole moment.",0805.0518v1
+2013-07-18,Interaction effect detected by compared of the irreversible and remanent initial magnetization curves in Ni-Cu-Zn ferrites,"A new technique for estimation of magnetic interaction effects of initial
+magnetization curves has been proposed. It deals with remanence, and initial
+irreversible magnetization, curves. The method is applied for single-phase
+polycrystalline Ni0.85-xCu0.15ZnxFe2O4, (x = 0, 0.2, 0.4 and 0.6), which were
+synthesized by a standard ceramic technology. A study of the initial reversible
+and irreversible magnetization processes in ferrite materials was carried out.
+The field dependence of the irreversible, and reversible, magnetizations was
+determined by magnetic losses of minor hysteresis loops obtained from different
+points of an initial magnetization curve. The influence of Zn-substitutions in
+Ni-Cu ferrites over irreversible magnetization processes and interactions in
+magnetic systems has been analyzed.",1307.4881v1
+2014-02-09,Synthesis of Fe3O4@CoFe2O4@MnFe2O4 trimagnetic core/shell/shell nanoparticles,"We report the synthesis and characterization of original 'multishell'
+magnetic nanoparticles made of a soft core (magnetite) covered with two
+successive shells: a hard one (cobalt ferrite) and then a soft one (manganese
+ferrite). Our results show that contrary to expectations from simple models in
+which the coercivity of a bimagnetic core/shell nanoparticle depends simply on
+the proportion of soft and hard phases within that particle, the addition of a
+second shell made of a soft ferrite material enhances the coercivity. Taking
+into account the interactions between the shells themselves and the core may
+thus be necessary to understand the magnetic properties of such nanoparticles.",1402.1950v1
+2013-08-01,Control of magnetization reversal in oriented Strontium Ferrite thin films,"Oriented Strontium Ferrite films with the c axis orientation were deposited
+with varying oxygen partial pressure on Al2O3(0001) substrate using PLD
+technique. The angle dependent magnetic hysteresis, remanent coercivity and
+temperature dependent coercivity had been employed to understand the
+magnetization reversal of these films. It was found that the Strontium Ferrite
+thin film grown at lower (higher) oxygen partial pressure shows
+Stoner-Wohlfarth type (Kondorsky like) reversal. The relative importance of
+pinning and nucleation processes during magnetization reversal is used to
+explain the type of the magnetization reversal with different oxygen partial
+pressure during growth.",1308.0171v1
+2019-10-15,3D Field Simulation Model for Bond Wire On-Chip Inductors Validated by Measurements,"This paper proposes 3D field simulation models for different designs of
+integrated bond wire on-chip inductors. To validate the simulation models,
+prototypes for three designs with air and ferrite cores are manufactured and
+measured. For air core inductors, high agreement between simulation and
+measurement is obtained. For ferrite core inductors, accurate models require an
+exact characterization of the ferrite material. These models enable the
+prediction of magnetic field influences on underlying integrated circuits.",1910.06831v1
+2018-12-16,Yttrium-substituted Mg-Zn ferrites: correlation of physical properties with Yttrium content,"Yttrium (Y) substituted Mg Zn ferrites with the compositions of
+Mg0.5Zn0.5YxFe2 xO4 have been synthesized by conventional standard ceramic
+technique. The effect of Y3+ substitution on the structural, electrical,
+dielectric and magnetic properties of Mg Zn ferrites has been studied.",1812.06370v2
+2019-02-23,Tailoring the crack-tip microstructure: A novel approach,"This investigation demonstrates a way to innovatively modify the ferritic
+microstructure at a local scale, particularly at the failure prone area such as
+Charpy V-notch (CVN) root. Tensile pre-strain (PS) up to 6 percent and 12
+percent were employed before annealing (An) the samples at 650{\deg}C for 15
+minutes. Ferrite grain size increased sharply and gradually (along the distance
+ahead of the notch root) within the microstructurally modified region in 6-12
+percent pre-strained and annealed samples, respectively. Critical strain which
+promotes strain induced boundary migration (SIBM), was found to be 0.1 which
+resulted in abnormally coarse ferrite grains.",1902.08797v1
+2019-08-04,Transparent Negative Index of Refraction Metamaterial Using a Wire Array in a Magnetic Host,"We have made measurements of microwave transmission over the 12 - 18 GHz
+range and through a simple metamaterial exhibiting a negative index of
+refraction. The metamaterial consisted of an array of wires cladded in
+dielectric embedded in a magnetic ferrite. The ferrite replaced the cut-ring
+structure usually used to create the negative permeability. The dielectric
+cladding decoupled the ferrite from the wires, thereby allowing the wire array
+permittivity to be simultaneously negative with the permeability. The
+simplicity of the design allows for miniaturization of potential microwave
+devices based on this metamaterial.",1908.01378v1
+2023-03-08,Construction and Testing of a Common Mode Choke for Cryogenic Detector Pre-Amplifiers,"Common-mode choke inductors are useful tools for resolving grounding issues
+in large detector systems. Using inductive components on cryogenic
+pre-amplifier boards has so far been prevented by the poor low-temperature
+performance of common ferrite materialssuch as NiZn and MnZn. Recentlydeveloped
+nanocrystallineand amorphous ferrite materials promise improved performance up
+to the point where using magnetics at liquid mitrogen temperatures becomes
+feasible. This research applies the work of Yin et al. on characterizing
+ferrite materials by constructing and testing a common mode choke inductor for
+use on detector pre-amplifiers for the ELT first generation instruments.",2303.04541v1
+2003-05-19,The anapole moments in disk-form MS-wave ferrite particle,"The anapole moments describe the parity-violating parity-odd,
+time-reversal-even couplings between elementary particles and the
+electromagnetic (EM) field. Surprisingly, the anapole-like moment properties
+can be found in certain artificially engineered physical systems. In
+microwaves, ferrite resonators with multi-resonance magnetostatic-wave
+(MS-wave) oscillations may have sizes two-four orders less than the free-space
+EM wavelength at the same frequency. MS-wave oscillations in a ferrite sample
+occupy a special place between the pure electromagnetic and spin-wave
+(exchange) processes. The energy density of MS-wave oscillations is not the
+electromagnetic-wave density of energy and not the exchange energy density as
+well. These microscopic oscillating objects -- the particles -- may interact
+with the external EM fields by a very specific way, forbidden for the classical
+description. To describe such interactions, the quantum mechanical analysis
+should be used. The presence of surface magnetic currents is one of the
+features of MS oscillations in a normally magnetized ferrite disk resonator.
+Because of such magnetic currents, MS oscillations in ferrite disk resonators
+become parity violating. The parity-violating couplings between disk-form
+ferrite particles and the external EM field should be analyzed based on the
+notion of an anapole moment.",0305431v1
+2007-12-14,Electric self inductance of quasi-2D magnetic-dipolar-mode ferrite disks,"An electric current flowing around a loop produces a magnetic field and hence
+a magnetic flux through the loop. The ratio of the magnetic flux to the
+electric current is called the (magnetic) self inductance. Can there be a dual
+situation with a magnetic current flowing around a loop and producing an
+electric field and hence an electric flux through the loop? Following the
+classical electrodynamics laws an answer to this question should be negative.
+Nevertheless special spectral properties of magnetic dipolar modes in a
+quasi-2D ferrite disk show there are the double-valued-function loop magnetic
+currents which may produce eigen electric fields and hence eigen electric
+fluxes through the loop. In this case one can definitely introduce the notion
+of the electric self inductance as the ratio of the electric flux to the
+magnetic current. In this paper we show experimentally that in the
+magnetic-dipolar-mode ferrite disks there exist eigen electric fluxes. These
+fluxes are very sensitive to permittivity parameters of materials abutting to
+the ferrite disk. Dielectric samples above a ferrite disk with a higher
+permittivity than air confine the electric field closely outside the ferrite,
+thereby changing the loop magnetic currents and thus transforming the
+magnetic-dipolar-mode oscillating spectrum.",0712.2305v1
+2014-07-14,Bismuth ferrite as low-loss switchable material for plasmonic waveguide modulator,"We propose new designs of plasmonic modulators, which can be utilized for
+dynamic signal switching in photonic integrated circuits. We study performance
+of plasmonic waveguide modulator with bismuth ferrite as an active material.
+The bismuth ferrite core is sandwiched between metal plates
+(metal-insulator-metal configuration), which also serve as electrodes so that
+the core changes its refractive index under applied voltage by means of partial
+in-plane to out-of-plane reorientation of ferroelectric domains in bismuth
+ferrite. This domain switch results in changing of propagation constant and
+absorption coefficient, and thus either phase or amplitude control can be
+implemented. Efficient modulation performance is achieved because of high field
+confinement between the metal layers, as well as the existence of mode cut-offs
+for particular values of the core thickness, making it possible to control the
+signal with superior modulation depth. For the phase control scheme, {\pi}
+phase shift is provided by 0.8-{\mu}m length device having propagation losses
+0.29 dB/{\mu}m. For the amplitude control, we predict up to 38 dB/{\mu}m
+extinction ratio with 1.2 dB/{\mu}m propagation loss. In contrast to previously
+proposed active materials, bismuth ferrite has nearly zero material losses, so
+bismuth ferrite based modulators do not bring about additional decay of the
+propagating signal.",1407.3734v1
+2017-08-16,"Role of pinning mechanism in co-precipitation derived cobalt rich, cobalt ferrite nanoparticles","Cobalt ferrite nanoparticles have been synthesized using a co-precipitation
+approach. Co:Fe precursor ratio is varied over a certain window (1.05 to 1.2).
+It is observed that the 1.15:2 precursor ratio gives better phase control but
+poor coercivity. On the other hand, 1.05:2 precursor ratio results in
+substantially better coercivity values (274kA/m; almost 300% the value reported
+for co-precipitated cobalt ferrite by Praveena et al.), but moderate BH product
+maximum (2.25 kJ/m3; ~ comparable to many reports on cobalt ferrite
+nanoparticles so far). The nanoparticles with best coercivity are annealed at
+873K for varying durations (2, 4, 6, 12 hrs). It is observed that the
+coercivity drops drastically (almost by 80%) after annealing for 2 hours.
+However thereafter coercivity and saturation magnetization improves marginally
+with increasing duration of annealing. These studies, along with
+thermogravimetric analysis, and infrared spectroscopic results indicate that a
+hydroxide nanophase based flux pinning mechanism at the grain boundary plays an
+important role in explaining the observed magnetic property trends. It is
+believed that this result will be generically helpful in developing soft
+chemically derived ferrites with higher coercivity and moderate (BH)max.
+However to develop plausible applications using the reported ferrites that use
+nanophase flux pinning, soft materials and device processing methods will need
+to be explored.",1708.04839v1
+2012-04-01,Topological-phase effects and path-dependent interference in microwave structures with magnetic-dipolar-mode ferrite particles,"Different ways exist in optics to realize photons carrying nonzero orbital
+angular momentum. Such photons with rotating wave fronts are called twisted
+photons. In microwaves, twisted fields can be produced based on small ferrite
+particles with magnetic-dipolar-mode (MDM) oscillations. Recent studies showed
+strong localization of the electric and magnetic energies of microwave fields
+by MDM ferrite disks. For electromagnetic waves irradiating MDM disks, these
+small ferrite samples appear as singular subwavelength regions with time and
+space symmetry breakings. The fields scattered by a MDM disk are characterized
+by topologically distinctive power-flow vortices and helicity structures. In
+this paper we analyze twisted states of microwave fields scattered by MDM
+ferrite disks. We show that in a structure of the fields scattered by MDM
+particles, one can clearly distinguish rotating topological-phase dislocations.
+Specific long-distance topological properties of the fields are exhibited
+clearly in the effects of path-dependent interference with two coupled MDM
+particles. Such double-twisted scattering is characterized by topologically
+originated split-resonance states. Our studies of topological-phase effects and
+path-dependent interference in microwave structures with MDM ferrite particles
+are based on numerical analysis and recently developed analytical models. We
+present preliminary experimental results aimed to support basic statements of
+our studies.",1204.0177v1
+2020-04-15,Synthesis optimization of Zn-Mn ferrites for magnetic fluid aplications,"Mn-Zn ferrite nanoparticles have been subject of increasing research due to
+their desired properties for a wide range of applications. These properties
+include nanometer particle size control, tunable magnetic properties and low
+toxicity, providing these ferrites with the necessary requirements for cancer
+treatment via magnetic hyperthermia. During this master thesis, powders of
+Mn1-xZnxFe2O4 (x=0; 0.5; 0.8; 1) were synthesized via the sol-gel
+autocombustion and hydrothermal methods, aiming to optimize their structural
+and magnetic properties for further application in a ferrofluid. Samples were
+characterized by XRD, SQUID, SEM, TEM and magnetic induction heating (MIH)
+techniques. The XRD diffractograms of hydrothermally produced samples present
+spinel crystal structure with high single-phase percentage (>88%). Rietveld
+refinement and Williamson-Hall analysis reveal a decrease of lattice constant
+and crystallite size with increase of Zn/Mn ratio. TEM images reveal narrow
+particle size distributions and decrease of the mean particle size with
+increase of Zn/Mn. SQUID results show that the increase of Zn results in a
+decrease of saturation magnetization and remnant magnetization. More
+noticeably, the M(T) curves present a shift in the samples magnetic ordering
+temperature towards lower temperatures with the increase of Zn content, from
+~556 to ~284 K. The MIH experiment also unveil a decrease in the heating rate
+with the increase of Zn. Nanocrystals of Mn-Zn ferrite produced by hydrothermal
+method present better crystallinity and magnetic properties than the sol-gel
+auto-combustion samples. The hydrothermally synthesized samples revealed
+dependence of its structural and magnetic properties with Mn/Zn ratio.The
+magnetic ordering temperature of these ferrites can be used as a
+self-controlled mechanism of heating, raising these ferrites to a class of
+smart materials.",2004.07006v2
+2023-01-04,Preparation and Characterization of NixMn0.25-xMg0.75Fe2O4 Nano-ferrite as NO2 Gas Sensing Material,"NixMn0.25-xMg0.75Fe2O4 nano-ferrites (where x = 0.00, 0.05, 0.10, 0.15 and
+0.20) were produced via sol-gel auto-combustion technique. Investigations were
+done into how the incorporation of Ni ions affects the Mn0.25Mg0.75Fe2O4
+ferrite's structure, morphological, magnetic, and NO2 gas sensing features. All
+the samples are single-phase, based on the structural study utilizing the X-ray
+diffraction (XRD) pattern. In terms of the structure of the cubic spinel,
+according to the XRD study, the crystallite sizes range from 24.30 to 28.32 nm,
+indicating nano-crystallinity. The synthesis of spherical nanoparticles with a
+small modification in particle size distribution was verified via FE-SEM
+images. The study found that the size of particles is tiny enough to act
+superparamagnetically. The area of hysteresis loop is almost non-existing, thus
+reflecting typical soft magnetic materials according to magnetic measurements
+by VSM carried out at room temperature. Furthermore, the conductance responses
+of the NixMn0.25-xMg0.75Fe2O4 nano-ferrite were measured by exposing the
+ferrite to oxidizing (NO2) gas at different operating temperatures. The results
+show that the sensor boasts shorter response and recovery times, as well as a
+higher sensitivity 707.22% of the sample (x=0.20) for nano-ferrite.",2301.01728v1
+2007-07-03,A new concept and design of ferrite-based microwave vortex devices,"In microwave resonant systems with ferrite samples, one becomes faced with
+specific phase relations for the electromagnetic fields. Such specific phase
+relations may lead to appearance of nontrivial states: electromagnetic
+vortices. This paper provides some general ideas and design principles for
+microwave devices with the field vortex structures.",0707.0350v1
+2008-12-12,Magnetoelectric Effect for Novel Microwave Device Applications,"In a normally magnetized thin-film ferrite disk with magnetic-dipolar modes,
+one can observe magnetoelectric oscillations. Such magnetoelectric properties
+of an electrically small sample can be considered as very attractive phenomena
+in microwaves. In this paper we discuss the question on novel microwave device
+applications based on ferrite magnetoelectric particles.",0812.2343v2
+2009-04-20,Quasi-Optical Characterization of Dielectric and Ferrite Materials,"Quasi-Optical Characterization of Dielectric and Ferrite Materials are made
+in the millimeter-submillimeter range by using a Quasi-Optical (QO) benches
+that can be relatively compact, typically of the order 10cm wide and 1m long.",0904.3069v1
+2014-07-17,Magnetic Properties of Bismuth Ferrite Nanopowder Obtained by Mechanochemical Synthesis,"Multiferroic bismuth ferrite (BiFeO3) nanopowders have been obtained in room
+temperature by mechanical synthesis. Depending on the post-synthesis processing
+the nanopowders have exhibited differences in the mean sizes, presence of
+amorphous layer and/or secondary phases. Extended magnetic study performed for
+fresh, annealed and hot-pressed nanopowders have revealed substantial
+improvement of the magnetic properties in the as-prepared powder.",1407.4657v1
+2018-04-16,Unidirectional Loop Metamaterials (ULM) as Magnetless Artificial Ferrimagnetic Materials: Principles and Applications,"This paper presents an overview of Unidirectional Loop Metamaterial (ULM)
+structures and applications. Mimicking electron spin precession in ferrites
+using loops with unidirectional loads (typically transistors), the ULM exhibits
+all the fundamental properties of ferrite materials, and represents the only
+existing magnetless ferrimagnetic medium. We present here an extended
+explanation of ULM physics and unified description of its component and system
+applications.",1804.08719v1
+2017-04-25,Characterization of Zinc oxide & Aluminum Ferrite and Simulation studies of M-H plots of Cobalt/Cobaltoxide,"Zinc oxide and Aluminum Ferrite were prepared Chemical route. The samples
+were characterized by XRD and VSM. Simulation of M-H plots of Co/CoO thin films
+were performed. Effect of parameters was observed on saturation magnetization.",1705.00525v2
+2003-06-19,Resonance magnetoelectric effects in layered magnetostrictive-piezoelectric composites,"Magnetoelectric interactions in bilayers of magnetostrictive and
+piezoelectric phases are mediated by mechanical deformation. Here we discuss
+the theory and companion data for magnetoelectric (ME) coupling at
+electromechanical resonance (EMR) in a ferrite-lead zirconate titanate (PZT)
+bilayer. Estimated ME voltage coefficient versus frequency profiles for nickel,
+cobalt, or lithium ferrite and PZT reveal a giant ME effect at EMR with the
+highest coupling expected for cobalt ferrite-PZT. Measurements of resonance ME
+coupling have been carried out on layered and bulk composites of nickel
+ferrite-PZT. We observe a factor of 40-600 increase in ME voltage coefficient
+at EMR compared to low frequency values. Theoretical ME voltage coefficients
+versus frequency profiles are in excellent agreement with data. The resonance
+ME effect is therefore a novel tool for enhancing the field conversion
+efficiency in the composites.",0306513v1
+2003-08-08,Low frequency and Microwave Magnetoelectric Effects in Thick Film Heterostructures of Lithium Zinc Ferrite and Lead Zirconate Titanate,"Magnetoelectric (ME) coupling at low frequencies and at x-band have been
+investigated in layered samples containing zinc substituted lithium ferrite and
+lead zirconate titanate (PZT). Multilayers of Li0.5-x/2ZnxFe2.5-x/2O4 (LZFO)
+(x=0-0.4) and PZT were prepared by lamination and sintering of thick films. At
+low frequencies (10-1000 Hz), the ME voltage coefficient for transverse fields
+is higher than for longitudinal fields. With Zn substitution in the ferrite,
+transverse coupling increases to a maximum for x=0.3 and then decreases for
+higher x. Analysis based on our model for a bilayer implies an efficient
+magneto-mechanical coupling with Zn substitution, resulting in strong ME
+interactions. Microwave ME coupling is studied through measurements of shift in
+the ferromagnetic resonance field due to an applied electric field. Estimated
+ME constants from such data are in agreement with our model for a ferrite-PZT
+bilayer.",0308171v1
+2003-10-23,On implementation of ferrite magnetostatic/magnetoelectric particles for quantum computation,"We consider an implementation of quantum gates for quantum computation using
+magnetostatic/magnetoelectric (MS/ME) macroscopically quantized states in small
+ferrite disks. Confinement phenomena for MS oscillations in a normally
+magnetized ferrite disk show typical atomic properties like discrete energy
+levels. Because of discrete energy eigenstates of MS oscillations, the
+oscillating system is described as a collective motion of quasi-particles - the
+light magnons. A macroscopic quantum analysis of MS oscillations underlines the
+physics of quantized ME oscillating spectrums in ferrite disks with surface
+electrodes. We discuss possible technologies for physical realization of new
+logic gates based on MS/ME-particle qubits.",0310558v1
+2009-08-30,Magnetic-dipolar-mode vortices and microwave subwavelength metamaterials,"There has been a surge of interest in the subwavelength confinement of the
+electromagnetic fields. It is well known that in optics the subwavelength
+confinement can be obtained due to surface plasmon (quasielectrostatic)
+oscillations. In this paper we propose to realize the subwavelength confinement
+in microwaves due to dipolar-mode (quasimagnetostatic) magnon oscillations in
+ferrite particles. Our studies of interactions between microwave
+electromagnetic fields and small ferrite particles with magnetic-dipolar-mode
+(MDM) oscillations show strong localization of electromagnetic energy. MDM
+oscillations in a ferrite disk are origins of topological singularities
+resulting in Poynting-vector vortices and symmetry breakings of the microwave
+near fields. We show that new subwavelength microwave metamaterials can be
+realized based on a system of interacting MDM ferrite disks. The volume- and
+surface-wave propagation of electromagnetic signals in the proposed dense
+metamaterials will be characterized by topological phase variations. The
+MDM-particle-metamaterial concept opens a significantly new area of research.
+In particular, there is a perspective for creation of engineered
+electromagnetic fields with unique symmetry properties.",0908.4383v1
+2011-03-30,Giant coercivity of dense nanostructured spark plasma sintered barium hexaferrite,"Due to the limited rare-earth elements resources, ferrite magnets need to be
+improved drastically. Ideally, for a true hard magnet, the coercive field
+should be larger than the saturation magnetization, which is not yet realized
+for ferrites. Thus, an alternative can be found in making very fine grain
+ferrite magnets, but it is usually impossible to get small grains and dense
+material together. In this paper, it is shown that the spark plasma sintering
+method is able to produce approximately 80% of dense material with crystallites
+smaller than 100 nm. The as-prepared bulk sintered anisotropic magnets exhibits
+coercive field of 0.5 T which is approximately 60% of the theoretical limit and
+only a few percentage below that of loose nanopowders. As a result, the magnets
+behave nearly ideal (-1.18 slope in the BH plane second quadrant) and the
+energy product reaches 8.8 kJ m-3, the highest value achieved in the isotropic
+ferrite magnet to our knowledge.",1103.5840v1
+2012-03-18,"Structural, magnetic, and optical properties of zinc- and copper- substituted nickel ferrite nanocrystals","Ferrite nanocrystals are interesting material due to their rich physical
+properties. Here we add nonmagnetic dopants Zn and Cu to nickel ferrite
+nanocrystals, Ni1-xMxFe2O4 (0<=x<=1, M{\in}{Cu, Zn}), and characterize how
+relevant properties of the samples are modified accordingly. Basically, these
+dopings cause a rearrangement of Fe+3 ions into the two preexisting octahedral
+and tetrahedral sites. In fact, this, we show, induces pertinent magnetic
+properties of the doped samples. In the case of the Cu-doping, the Jahn-Teller
+effect also emerges, which we identify through the FTIR Spectroscopy of the
+samples. Moreover, we show an increase in the lattice parameters of the doped
+samples, as well a superparamagnetic behavior for the doped samples is shown,
+while the Jahn-Teller effect precludes a similar behavior in the CuFe2O4
+nanocrystals. The influences of Zn and Cu substitutions are investigated on the
+optical properties of nickel ferrite nanocrystals by photoluminescence
+measurement at room temperature.",1203.3924v1
+2016-07-17,Third Order Perturbed Heisenberg Hamiltonian of Thick Spinel Ferrite Films,"The third order perturbed Heisenberg Hamiltonian was employed to investigate
+the spinel thick nickel ferrite films. The variation of energy up to N=10000
+was studied. At N=75, the energy required to rotate from easy to hard direction
+is very small. For film with N=10000, the first major maximum and minimum can
+be observed at 202 and 317 degrees, respectively. This curve shows some abrupt
+changes after introducing third order perturbation. The maximum energy of this
+curve is higher than that of spinel thick ferrite films with second order
+perturbed Heisenberg Hamiltonian. At some values of stress induced anisotropy,
+the maximum energy is less than that of spinel thick ferrite films with second
+order perturbed Heisenberg Hamiltonian derived by us previously.",1611.02230v1
+2017-01-18,Azimuthally unidirectional transport of energy in magnetoelectric fields. Topological Lenz effect,"Magnetic dipolar modes (MDMs) in a quasi 2D ferrite disk are microwave energy
+eigenstate oscillations with topologically distinct structures of rotating
+fields and unidirectional power flow circulations. At the first glance, this
+might seem to violate the law of conservation of an angular momentum, since the
+microwave structure with an embedded ferrite sample is mechanically fixed.
+However, an angular momentum is seen to be conserved if topological properties
+of electromagnetic fields in the entire microwave structure are taken into
+account. In this paper we show that due to the topological action of the
+azimuthally unidirectional transport of energy in a MDM resonance ferrite
+sample there exists the opposite topological reaction on a metal screen placed
+near this sample. We call this effect topological Lenz effect. The topological
+Lenz law is applied to opposite topological charges, one in a ferrite sample
+and another on a metal screen. The MDM originated near fields, the
+magnetoelectric (ME) fields, induce helical surface electric currents and
+effective charges on a metal. The fields formed by these currents and charges
+will oppose their cause.",1701.05185v1
+2017-04-04,Magnetic Dipole Interaction and Total Magnetic Energy of Lithium Ferrire Thin Films,"The total magnetic energy of Lithium ferrite thin films was determined using
+the classical Heisenberg Hamiltonian. The short range magnetic dipole
+interactions between spins within one unit cell and the interactions between
+spins in two adjacent unit cells have been determined in order to find the
+total magnetic energy of lithium ferrite films. Only the spin pairs with
+separation less than cell constant have been taken into account to calculate
+dipole interaction and spin exchange interaction. Theoretically several easy
+and hard directions of lithium ferrite film were found for one set of energy
+parameters included in our modified Heisenberg Hamiltonian. The dependence of
+total magnetic energy of a lithium ferrite film on number of unit cells, spin
+exchange interaction, dipole interaction, second order magnetic anisotropy,
+fourth order magnetic anisotropy, internal applied magnetic field and stress
+induced magnetic anisotropy has been explained in this manuscript.",1704.03314v1
+2013-09-16,Epitaxial Growth of Spinel Cobalt Ferrite Films on MgAl$_2$O$_4$ Substrates by Direct Liquid Injection Chemical Vapor Deposition,"The direct liquid injection chemical vapor deposition (DLI-CVD) technique has
+been used for the growth of cobalt ferrite (CFO) films on (100)-oriented
+MgAl$_2$O$_4$ (MAO) substrates. Smooth and highly epitaxial cobalt ferrite thin
+films, with the epitaxial relationship $\mathrm{MAO} (100)\:[001] \parallel
+\mathrm{CFO} (100)\:[001]$, are obtained under optimized deposition conditions.
+The films exhibit bulk-like structural and magnetic properties with an
+out-of-plane lattice constant of $8.370\;\mathrm{\AA}$ and a saturation
+magnetization of $420\;\mathrm{kA/m}$ at room temperature. The Raman spectra of
+films on MgAl$_2$O$_4$ support the fact that the Fe$^{3+}$- and the
+Co$^{2+}$-ions are distributed in an ordered fashion on the B-site of the
+inverse spinel structure. The DLI-CVD technique has been extended for the
+growth of smooth and highly oriented cobalt ferrite thin films on a variety of
+other substrates, including MgO, and piezoelectric lead magnesium niobate-lead
+titanate and lead zinc niobate-lead titanate substrates.",1309.4031v1
+2018-08-10,Role of disconnections in mobility of the austenite-ferrite inter-phase boundary in Fe,"Austenite ({\gamma}-Fe, face centered cubic (FCC)) to ferrite ({\alpha}-Fe,
+body centered cubic (BCC)) phase transformation in steel is of great
+significance from the point of view of industrial applications. In this work,
+using classical molecular dynamics simulations, we study the atomistic
+mechanisms involved during the nucleation and growth of the ferrite phase
+embedded in an austenite phase. We find that the disconnections present at the
+inter-phase boundary can act as the nucleation centers for the ferrite phase.
+Relatively small interface velocities (1.19 - 4.67 m/s) confirm a phase change
+via massive transformation mechanism. Boundary mobilities obtained in a
+temperature range of 1000 to 1400 K show an Arrhenius behavior, with activation
+energies ranging from 30 - 40 kJ/mol.",1808.03432v2
+2020-10-28,On the happiness of ferroelectric surfaces and its role in water dissociation: the example of bismuth ferrite,"We investigate, using density functional theory, how the interaction between
+the ferroelectric polarization and the chemical structure of the (001) surfaces
+of bismuth ferrite influences the surface properties and reactivity of this
+material. A precise understanding ofthe surface behavior of ferroelectrics is
+necessary for their use in surface science applications such as catalysis as
+well as for their incorporation in microelectronic devices. Using the (001)
+surface of bismuth ferrite as a model system we show that the most
+energetically favoured surface geometries are combinations of surface
+termination and polarization direction that lead to uncharged, stable surfaces.
+On the unfavorable charged surfaces, we explore the compensation mechanisms of
+surface charges provided by the introduction of point defects and adsorbates,
+such as water. Finally, we propose that the special surface properties of
+bismuth ferrite (001) could be used to produce an effective water splitting
+cycle through cyclic polarization switching.",2010.14895v1
+2022-05-12,"Structural, Dielectric, and Electrical Transport Properties of Al3+ Substituted Nanocrystalline Ni-Cu Spinel Ferrites Prepared Through the Sol-Gel Route","In this study, a series of nanocrystalline ferrites of Ni0.7Cu0.30AlxFe2-xO4
+(x=0.00 to 0.10 with a step of 0.02) has been synthesized through the sol-gel
+auto combustion technique. The structural, morphological, dielectric, and
+electrical properties of the Ni-Cu spinel ferrite nanoparticles are analyzed
+due to the substitution of Al3+ content. The crystalline and structural
+characteristics of the prepared nanoparticles (NPs) have been studied employing
+the x-ray diffraction (XRD) spectra and FTIR analysis. The extracted XRD
+patterns assure the single-phase cubic spinel structure of all samples with
+homogeneity and no impurity, which indicates the yielding of high crystalline
+NPs. A slight decrease of average grain size with increment of Al3+ content is
+observed in the surface morphological study carried out by the field emission
+scanning electron microscopy (FESEM). The studied materials are found in
+semi-spherical shapes, showing the multi-domain grains separated by grain
+boundaries with some agglomerations. The chemical composition study for the
+synthesized NI-Cu spinel ferrites using energy dispersive x-ray (EDX) ensures
+the presence of each component in appropriate proportions in each sample.",2205.06233v1
+2023-05-24,Time-reversal Invariance Violation and Quantum Chaos Induced by Magnetization in Ferrite-Loaded Resonators,"We investigate the fluctuation properties in the eigenfrequency spectra of
+flat cylindrical microwave cavities that are homogeneously filled with
+magnetized ferrite. These studies are motivated by experiments in which only
+small pieces of ferrite were embedded in the cavity and magnetized with an
+external static magnetic field to induce partial time-reversal (T ) invariance
+violation. We use two different shapes of the cavity, one exhibiting an
+integrable wave dynamics, the other one a chaotic one. We demonstrate that in
+the frequency region where only transverse-magnetic modes exist, the
+magnetization of the ferrites has no effect on the wave dynamics and does not
+induce T -invariance violation whereas it is fully violated above the cutoff
+frequency of the first transverse-electric mode. Above all, independently of
+the shape of the resonator, it induces a chaotic wave dynamics in that
+frequency range in the sense that for both resonator geometries the spectral
+properties coincide with those of quantum systems with a chaotic classical
+dynamics and same invariance properties under application of the generalized T
+operator associated with the resonator geometry.",2305.14753v1
+2024-02-19,Broadband ferromagnetic resonance in Mn-doped Li ferrite nanoparticles,"Lithium ferrites are well known materials due to their numerous technological
+applications especially in microwave devices. Mn-doped lithium ferrite
+nanoparticles were prepared by sol-gel technique by means of Pechini method,
+and then annealed at different temperatures in 250 to 1000 {\deg}C range. XRD
+confirms spinel formation with particle size in the 15 to 200 nm range, with
+increased size with annealing temperature. Microwave magnetoabsorption data of
+annealed lithium ferrite nanoparticles, obtained with a broadband system based
+on a network analyzer operating up to 8.5 GHz are presented. At fields up to
+200 mT we can observe a broad absorption peak that shifts to higher frequencies
+with magnetic field according to ferromagnetic resonance theory. The amplitude
+of absorption, up to 85%, together with the frequency width of about 4.5 GHz
+makes this material suitable as wave absorber. Samples annealed at higher
+temperatures show a behaviour similar to polycrystalline samples, thus
+suggesting their multidomain character",2402.12096v1
+2001-07-05,"Two Modes of Solid State Nucleation - Ferrites, Martensites and Isothermal Transformation Curves","When a crystalline solid such as iron is cooled across a structural
+transition, its final microstructure depends sensitively on the cooling rate.
+For instance, an adiabatic cooling across the transition results in an
+equilibrium `ferrite', while a rapid cooling gives rise to a metastable twinned
+`martensite'. There exists no theoretical framework to understand the dynamics
+and conditions under which both these microstructures obtain. Existing theories
+of martensite dynamics describe this transformation in terms of elastic strain,
+without any explanation for the occurence of the ferrite. Here we provide
+evidence for the crucial role played by non-elastic variables, {\it viz.},
+dynamically generated interfacial defects. A molecular dynamics (MD) simulation
+of a model 2-dimensional (2d) solid-state transformation reveals two distinct
+modes of nucleation depending on the temperature of quench. At high
+temperatures, defects generated at the nucleation front relax quickly giving
+rise to an isotropically growing `ferrite'. At low temperatures, the defects
+relax extremely slowly, forcing a coordinated motion of atoms along specific
+directions. This results in a twinned critical nucleus which grows rapidly at
+speeds comparable to that of sound. Based on our MD results, we propose a
+solid-state nucleation theory involving the elastic strain and non-elastic
+defects, which successfully describes the transformation to both a ferrite and
+a martensite. Our work provides useful insights on how to formulate a general
+dynamics of solid state transformations.",0107098v2
+2003-03-11,Magnetic artificial atoms based on thin-film ferrite disk particles,"Semiconductor quantum wells can be considered as an example of artificial
+atoms. Following the ideas used in the effective-mass theory, one can describe
+electron states in the quantum-well structure based on the Schrodinger-like
+equation for the envelope function. In recent years, there has been a renewed
+interest in high frequency dynamic properties of finite size magnetic
+structures. In a series of new publications, confinement phenomena of
+high-frequency magnetization dynamics in magnetic particles have been the
+subject of much experimental and theoretical attention. Till now, however,
+there are no phenomenological models of a ferrite particle with high-frequency
+magnetization dynamics that use the effective-mass approximation and the
+Schrodinger-like equation to analyze energy eigenstates of a whole
+ferrite-particle system, similarly to semiconductor quantum wells.
+Magnetostatic (MS) oscillations in ferrite samples have the wavelength much
+smaller than the electromagnetic wavelength at the same frequency and, at the
+same time, much larger than the exchange-interaction spin wavelength. This
+intermediate position between the pure electromagnetic and spin-wave
+(exchange-interaction) processes reveals very special behaviors of the
+geometrical effects. The confined effects for MS oscillations in normally
+magnetized thin-film ferrite disks demonstrate very unique properties of
+artificial atomic structures.",0303196v1
+2009-09-27,Space-time symmetry violation of the fields in quasi-2D ferrite particles with magnetic-dipolar-mode oscillations,"In magnetic systems with reduced dimensionality, the effects of dipolar
+interactions allow the existence of long-range ordered phases. Long-range
+magnetic-dipolar interactions are at the heart of the explanation of many
+peculiar phenomena observed in nuclear magnetic resonance, ferromagnetic
+resonance, and Bose-Einstein-condensate structures. In this paper we show that
+magnetic-dipolar-modes (MDMs) in quasi-2D ferrite disks are characterized by
+symmetry breaking effects. Our analysis is based on postulates about a physical
+meaning of the magnetostatic-potential function as a complex scalar wave
+function, which presumes the long-range phase correlations. An important
+feature of the MDM oscillations in a ferrite disk concerns the fact that a
+structure with symmetric parameters and symmetric basic equations goes into
+eigenstates that are not space-time symmetric. The proper solutions are found
+based on an analysis of magnetostatic-wave propagation in a helical coordinate
+system. For a ferrite disk, we show that while a composition of two helical
+waves may acquire a geometrical phase over-running of during a period, every
+separate helical wave has a dynamical phase over-running of and so behaves as a
+double-valued function. We demonstrate that unique topological structures of
+the fields in a ferrite disk are intimately related to the symmetry breaking
+properties of MDM oscillations. The solutions give the MDM power-flow-density
+vortices with cores at the disk center and azimuthally running waves of
+magnetization. One can expect that the proposed models of long-range ordered
+phases and space-time violation properties of magnetic-dipolar interactions can
+be used in other magnetic structures, different from the
+ferromagnetic-resonance system with reduced dimensionality.",0909.4920v1
+2013-07-18,Numerical response of the magnetic permeability as a funcion of the frecuency of NiZn ferrites using Genetic Algorithm,"The magnetic permeability of a ferrite is an important factor in designing
+devices such as inductors, transformers, and microwave absorbing materials
+among others. Due to this, it is advisable to study the magnetic permeability
+of a ferrite as a function of frequency.
+  When an excitation that corresponds to a harmonic magnetic field \textbf{H}
+is applied to the system, this system responds with a magnetic flux density
+\textbf{B}; the relation between these two vectors can be expressed as
+\textbf{B}=$\mu(\omega)$ \textbf{H} . Where $\mu$ is the magnetic permeability.
+  In this paper, ferrites were considered linear, homogeneous, and isotropic
+materials. A magnetic permeability model was applied to NiZn ferrites doped
+with Yttrium.
+  The parameters of the model were adjusted using the Genetic Algorithm. In the
+computer science field of artificial intelligence, Genetic Algorithms and
+Machine Learning does rely upon nature's bounty for both inspiration nature's
+and mechanisms. Genetic Algorithms are probabilistic search procedures which
+generate solutions to optimization problems using techniques inspired by
+natural evolution, such as inheritance, mutation, selection, and crossover.
+  For the numerical fitting usually is used a nonlinear least square method,
+this algorithm is based on calculus by starting from an initial set of variable
+values. This approach is mathematically elegant compared to the exhaustive or
+random searches but tends easily to get stuck in local minima. On the other
+hand, random methods use some probabilistic calculations to find variable sets.
+They tend to be slower but have greater success at finding the global minimum
+regardless of the initial values of the variables",1307.5007v1
+2015-03-01,Microwave magnetoelectric fields: An analytical study of topological characteristics,"The near fields originated from a small quasi-two-dimensional ferrite disk
+with magnetic-dipolar-mode (MDM) oscillations are the fields with broken dual
+(electric-magnetic) symmetry. Numerical studies show that such fields, called
+the magnetoelectric (ME) fields, are distinguished by the power-flow vortices
+and helicity parameters [E. O. Kamenetskii, R. Joffe, and R. Shavit, Phys. Rev.
+E 87, 023201 (2013)]. These numerical studies can well explain recent
+experimental results with MDM ferrite disks. In the present paper, we obtain
+analytically topological characteristics of the ME-field modes. For this
+purpose, we use a method of successive approximations. In the second
+approximation we take into account the influence of the edge regions of an open
+ferrite disk, which are excluded in the first-approximation solving of the
+magnetostatic (MS) spectral problem. Based on the analytical method, we obtain
+a 'pure' structure of the electric and magnetic fields outside the MDM ferrite
+disk. The analytical studies can display some fundamental features that are
+non-observable in the numerical results. While in numerical investigations, one
+cannot separate the ME fields from the external electromagnetic (EM) radiation,
+the present theoretical analysis allows clearly distinguish the eigen
+topological structure of the ME fields. Importantly, this ME-field structure
+gives evidence for certain phenomena that can be related to the Tellegen and
+bianisotropic coupling effects. We discuss the question whether the MDM ferrite
+disk can exhibit properties of the cross magnetoelectric polarizabilities.",1503.00270v2
+2020-01-18,The sensitivity of the microstructure and properties to the peak temperature in an ultrafast heat treated low carbon-steel,"In this work, we investigate the sensitivity of the microstructure and
+mechanical properties of an ultrafast heat treated low carbon-steel to the peak
+temperature. In all studied cases, the steel was heated within the
+intercritical temperature range (i.e. between the AC1 and AC3 temperatures).
+Both the peak temperature and soaking time were varied, and their effect on the
+size, the fraction of individual microstructural constituents and their tensile
+mechanical response were investigated. It is shown that the increasing peak
+temperature and soaking time promote austenite formation and recrystallization
+processes in the ferritic matrix. The highest nanohardness is shown by
+martensitic grains, while recovered ferrite demonstrated slightly higher
+nanohardness compared to recrystallized ferrite. The applied heat treatment
+parameters have strong effect on the nanohardness of martensite, whereas
+nanohardness of ferrite microconstituents is not sensitive to variation of the
+peak temperature and soaking time. The non-recrystallized ferrite is harder
+than its recrystallized counterpart due to the higher dislocation density of
+the former. Increasing peak temperatures promote strengthening in the material
+at the expense of its ductility mainly due to increased martensite fraction.
+The steel demonstrates enhanced strain hardening ability independently of the
+peak temperature. Analysis of the experimental results showed that the
+industrial processing window of +- 10 oC may lead to some heterogeneity of the
+local microstructure in the ultrafast heat treated sheets. However, the latter
+should not have any negative effect on the overall mechanical behavior of the
+ultrafast heat treated steel sheets on the macro-scale.",2001.06713v1
+2018-03-26,Enhancement of the magnetoelectric effect in multiferroic CoFe$_2$O$_4$/PZT bilayer by induced uniaxial magnetic anisotropy,"In this study we have compared magnetic, magnetostrictive and piezomagnetic
+properties of isotropic and anisotropic cobalt ferrite pellets. The isotropic
+sample was prepared by the ceramic method while the sample exhibiting uniaxial
+anisotropy was made by reactive sintering using Spark Plasma Sintering (SPS).
+This technique permits to induce a magnetic anisotropy in cobalt ferrite in the
+direction of the applied pressure during SPS process. Sample with uniaxial
+anisotropy revealed a higher longitudinal magnetostriction and piezomagnetism
+compared to the isotropic sample, but the transversal magnetostriction and
+piezomagnetism were dramatically reduced. In the case of magnetoelectric
+layered composite, the magnetoelectric coefficient is directly related to the
+sum of the longitudinal and transversal piezomagnetic coefficients. These two
+coefficients being opposite in sign, the use of material exhibiting high
+longitudinal and low transversal piezomagnetic coefficient (or vice versa) in
+ME devices is expected to improve the ME effect. Hence, ME bilayer devices were
+made using isotropic and anisotropic cobalt ferrite stuck with a PZT layer. ME
+measurements at low frequencies revealed that bilayer with anisotropic cobalt
+ferrite exhibits a ME coefficient three times higher than a bilayer with
+isotropic cobalt ferrite. We also investigated the behavior of such composites
+when excited at resonant frequency.",1803.09677v1
+2023-09-18,Computational Exploration of Magnetic Saturation and Anisotropy Energy for Nonstoichiometric Ferrite Compositions,"A grand challenge in materials research is identifying the relationship
+between composition and performance. Herein, we explore this relationship for
+magnetic properties, specifically magnetic saturation (M$_s$) and magnetic
+anisotropy energy (MAE) of ferrites. Ferrites are materials derived from
+magnetite (which has the chemical formulae Fe$_3$O$_4$) that comprise metallic
+elements in some combination such as Fe, Mn, Ni, Co, Cu and Zn. They are used
+in a variety of applications such as electromagnetism, magnetic hyperthermia,
+and magnetic imaging. Experimentally, synthesis and characterization of
+magnetic materials is time consuming. In order to create insight to help guide
+synthesis, we compute the relationship between ferrite composition and magnetic
+properties using density functional theory (DFT). Specifically, we compute
+M$_s$ and MAE for 571 ferrite structures with the formulae
+M1$_x$M2$_y$Fe$_{3-x-y}$O$_4$, where M1 and M2 can be Mn, Ni, Co, Cu and/or Zn
+and 0 $\le$ x $\le$ 1 and y = 1 - x. By varying composition, we were able to
+vary calculated values of M$_s$ and MAE by up to 9.6$\times$10$^5$ A m$^{-1}$
+and 14.1$\times$10$^5$ J m$^{-3}$, respectively. Our results suggest that
+composition can be used to optimize magnetic properties for applications in
+heating, imaging, and recording. This is mainly achieved by varying M$_s$, as
+these applications are more sensitive to variation in M$_s$ than MAE.",2309.09754v1
+1997-09-02,First Passage Times and Time-Temperature-Transformation curves for Martensites,"Martensites are long-lived nonequilibrium structures produced following a
+quench across a solid state structural transition. In a recent paper (Phys.
+Rev. Lett. 78, 2168 (1997)), we had described a mode-coupling theory for the
+morphology and nucleation kinetics of the equilibrium ferrite phase and twinned
+martensites. Here we calculate nucleation rates within a first-passage time
+formalism, and derive the time-temperature-transformation (TTT) diagram of the
+ferrite-martensite system for athermal and isothermal martensites. Empirically
+obtained TTT curves are extensively used by metallurgists to design heat
+treatment cycles in real materials.",9709022v1
+2002-02-17,Faraday rotation and sensitivity of (100) bismuth-substituted ferrite garnet films,"We have investigated the Faraday rotation of in-plane magnetized bismuth -
+substituted ferrite garnet films grown by liquid phase epitaxy on (100)
+oriented gadolinium gallium garnet substrates. The Faraday spectra were
+measured for photon energies between 1.7 - 2.6 eV. To interprete the spectra,
+we use a model based on two electric dipole transitions, one tetrahedral and
+one octahedral. Furthermore, the Faraday rotation sensitivity was measured at
+2.3 eV, and found to be in good agreement with the theoretical predicitions. In
+particular, we find that the sensitivity increases linearly with the bismuth
+content and nonlinearly with the gallium content.",0202281v1
+2003-07-12,"Magnetic and microwave properties of (Ni,Co)Fe2O4-ferroelectric and (La,Ca,Sr)MnO3-ferroelectric multilayer structures","Structural, magnetic and ferromagnetic resonance characterization studies
+have been performed on lay-ered ferromagnetic-ferroelectric oxides that show
+strong magnetoelectric coupling. The samples contained thick films of ferrites
+or substituted lanthanum manganites for the ferromagnetic phase and lead
+zirconate titanate for the ferroelectric phase, and were sintered high
+temperatures. Results indicate defect free ferrites, but deterioration of
+manganite parameters due to diffusion at the interface and accounts for poor
+magnetoelectric coupling in manganite-PZT samples.",0307302v1
+2004-09-01,Mesoscopic quantized properties of magnetic-dipolar-mode oscillations in disk ferromagnetic particles,"Magnetic dipolar mode or magnetostatic (MS) oscillations in ferrite samples
+have the wavelength much smaller than the electromagnetic wavelength at the
+same frequency and, at the same time, much larger than the exchange interaction
+spin wavelength. This intermediate position between the electromagnetic and
+spin wave (exchange interaction) processes reveals very special behaviors of
+the geometrical effects. It was shown recently that magnetic dipolar mode
+oscillations in a normally magnetized ferromagnetic disk are characterized by
+discrete energy levels resulting from the structural confinement. In this
+article we give results of the energy spectra in MS wave ferrite disks taking
+into account nonhomogeneity of the internal DC magnetic field.",0409023v1
+2005-05-30,Dynamical Symmetry Breaking in Quasistatic Magnetic Oscillations,"Recent microwave experiments demonstrate the anapole-moment and
+magnetoelectric properties in quasi-2D ferrite particles with
+magnetic-dipolar-wave oscillating spectra. The theory developed in this paper
+shows that there are the macroscopically quantum topological effects. Quantum
+coherence for macroscopic systems refers to circumstances when large numbers of
+particles can collectively cooperate in a single quantum state. These effects
+are rarely observed through macroscopic measurements because statistical
+averaging over many states usually masks all evidence of quantum discreteness.
+Magnetic-dipolar oscillating modes in normally magnetized ferrite disks
+demonstrate properties of a Hamiltonian system. The purpose of this paper is to
+show that because of the adiabatic motion process for such a Hamiltonian system
+one has macroscopic quantum effects of symmetry breaking, magnetic currents,
+and eigen electric moments.",0505717v1
+2007-03-14,Phase Separation of Bismuth Ferrite into Magnetite under Voltage Stressing,"Micro-Raman studies show that under ~700 kV/cm of d.c. voltage stressing for
+a few seconds, thin-film bismuth ferrite BiFeO3 phase separates into magnetite
+Fe3O4. No evidence is found spectroscopically of hemite alpha-Fe2O3, maghemite
+gamma-Fe2O3, or of Bi2O3. This relates to the controversy regarding the
+magnitude of magnetization in BiFeO3.",0703388v1
+2001-05-01,Rectangular microwave resonators with magnetic anisotropy. Mapping onto pseudo integrable rhombus,"The rectangular microwave resonator filed by a ferrite with uniaxial magnetic
+anisotropy is considered. It is shown that this task can be reduced to an empty
+rhombus resonator with vertex angle defined by external magnetic field provided
+the magnetic anisotropy of the ferrite is strong. Therefore statistics of eigen
+frequencies for TM modes is described by the Brody or semi-Poisson distribution
+with some exceptional cases.",0105001v1
+2004-02-11,Plane waves with negative phase velocity in Faraday chiral mediums,"The propagation of plane waves in a Faraday chiral medium is investigated.
+Conditions for the phase velocity to be directed opposite to the direction of
+power flow are derived for propagation in an arbitrary direction; simplified
+conditions which apply to propagation parallel to the distinguished axis are
+also established. These negative phase-velocity conditions are explored
+numerically using a representative Faraday chiral medium, arising from the
+homogenization of an isotropic chiral medium and a magnetically biased ferrite.
+It is demonstrated that the phase velocity may be directed opposite to power
+flow, provided that the gyrotropic parameter of the ferrite component medium is
+sufficiently large compared with the corresponding nongyrotropic permeability
+parameters.",0402057v1
+2008-01-26,Magnetoelectric Control of Domain Walls in a Ferrite Garnet Film,"The effect of magnetic domain boundaries displacement induced by electric
+field is observed in epitaxial ferrite garnet films (on substrates with the
+(210) crystallographic orientation). The effect is odd with respect to the
+electric field (the direction of wall displacement changes with the polarity of
+the voltage) and even with respect to the magnetization in domains. The
+inhomogeneous magnetoelectric interaction as a possible mechanism of the effect
+is proposed.",0801.4073v1
+2010-12-28,Transmission Electron Microscopy Studies on RF Sputtered Copper Ferrite Thin Films,"Copper ferrite thin films were rf sputtered at a power of 50W. The as
+deposited films were annealed in air at 800{\deg}C and slow cooled. The
+transmission electron microscope (TEM) studies were carried out on as deposited
+as well as on slow cooled film. Significantly larger defect concentration,
+including stacking faults, was observed in 50W as deposited films than the
+films deposited at a higher rf power of 200W. The film annealed at 800{\deg}C
+and then slow cooled showed an unusual grain growth upto 180nm for a film
+thickness of ~240nm. These grains showed Kikuchi pattern.",1012.5743v1
+2011-03-25,Temperature dependence of spin resonance in cobalt substituted NiZnCu ferrites,"Cobalt substitutions were investigated in Ni0.4Zn0.4Cu0.2Fe2O4 ferrites,
+initial complex permeability was then measured from 1 MHz to 1 GHz. It appears
+that cobalt substitution led to a decrease in the permeability and an increase
+in the \mus\timesfr factor. As well, it gave to the permeability spectrum a
+sharp resonance character. We also observed a spin reorientation occurring at a
+temperature depending on the cobalt content. Study of the complex permeability
+versus temperature highlighted that the most resonant character was obtained at
+this temperature. This shows that cobalt contribution to second order
+magnetocrystalline anisotropy plays a leading role at this temperature.",1103.5024v1
+2013-04-26,Ferroelectricity from iron valence ordering in rare earth ferrites?,"The possibility of multiferroicity arising from charge ordering in LuFe2O4
+and structurally related rare earth ferrites is reviewed. Recent experimental
+work on macroscopic indications of ferroelectricity and microscopic
+determination of coupled spin and charge order indicates that this scenario
+does not hold. Understanding the origin of the experimentally observed charge
+and spin order will require further theoretical work. Other aspects of recent
+research in these materials, such as geometrical frustration effects, possible
+electric-field-induced transitions, or orbital order are also briefly treated.",1304.7255v1
+2014-07-07,"Multiferroic hexagonal ferrites (h-RFeO$_3$, R=Y, Dy-Lu): an experimental review","Hexagonal ferrites (h-RFeO$_3$, R=Y, Dy-Lu) have recently been identified as
+a new family of multiferroic complex oxides.
+  The coexisting spontaneous electric and magnetic polarizations make
+h-RFeO$_3$ rare-case ferroelectric ferromagnets at low temperature.
+  Plus the room-temperature multiferroicity and predicted magnetoelectric
+effect, h-RFeO$_3$ are promising materials for multiferroic applications.
+  Here we review the structural, ferroelectric, magnetic, and magnetoelectric
+properties of h-RFeO$_3$.
+  The thin film growth is also discussed because it is critical in making high
+quality single crystalline materials for studying intrinsic properties.",1407.1798v1
+2015-01-29,Chiral-field microwave antennas (Chiral microwave near fields for far-field radiation),"In a single-element structure we obtain a radiation pattern with a squint due
+to chiral microwave near fields originated from a magnetostatic-mode ferrite
+disk. At the magnetostatic resonances, one has strong subwavelength
+localization of energy of microwave radiation. Magnetostatic oscillations in a
+thin ferrite disk are characterized by unique topological properties: the
+Poynting-vector vortices and the field helicity. The chiral-topology near
+fields allow obtaining unique phase structure distribution for far-field
+microwave radiation.",1501.07387v1
+2015-07-21,Frequency-dependent effective permeability tensor of unsaturated polycrystalline ferrites,"Frequency-dependent permeability tensor for unsaturated polycrystalline
+ferrites is derived through an effective medium approximation that combines
+both domain-wall motion and rotation of domains in a single consistent
+scattering framework. Thus derived permeability tensor is averaged on a
+distribution function of the free energy that encodes paramagnetic states for
+anhysteretic loops. The initial permeability is computed and frequency spectra
+are given by varying macroscopic remanent field.",1507.05814v1
+2016-11-03,Room temperature multiferroism in polycrystalline thin films of gallium ferrite,"Sol-gel deposited (010) textured polycrystalline thin films of gallium
+ferrite (GaFeO3 or GFO) on n-Si(100) and Pt/Si(111) substrates are
+characterized for room temperature multiferroism. Structural characterization
+using X-ray diffraction and Raman spectroscopy confirms formation of single
+phase with nano-sized crystallites. Temperature dependent magnetization study
+demonstrates ferri to paramagnetic transition at ~300 K. Room temperature
+piezoresponse force microscopic analysis reveals local 180 degree phase
+switching of ferroelectric domains at very high coercive field EC, ~ 1350 kV/cm
+consistent with recent experimental and first-principles studies. Our study
+opens up possibility of integrating polycrystalline GFO in novel room
+temperature multiferroic devices.",1611.01128v1
+2012-04-13,Spin Glass-like Phase below ~ 210 K in Magnetoelectric Gallium Ferrite,"In this letter we show the presence of a spin-glass like phase in single
+crystals of magnetoelectric gallium ferrite (GaFeO3) below ~210 K via
+temperature dependent ac and dc magnetization studies. Analysis of frequency
+dispersion of the susceptibility peak at ~210 K using the critical slowing down
+model and Vogel-Fulcher law strongly suggests the existence of a classical
+spin-glass like phase. This classical spin glass behavior of GaFeO3 is
+understood in terms of an outcome of geometrical frustration arising from the
+inherent site disorder among the antiferromagnetically coupled Fe ions located
+at octahedral Ga and Fe sites.",1204.2973v1
+2015-12-24,Polaritons dispersion in a composite ferrite-semiconductor structure near gyrotropic-nihility state,"In the context of polaritons in a ferrite-semiconductor structure which is
+influenced by an external static magnetic field, the gyrotropic-nihility can be
+identified from the dispersion equation related to bulk polaritons as a
+particular extreme state, at which the longitudinal component of the
+corresponding constitutive tensor and bulk constant simultaneously acquire
+zero. Near the frequency of the gyrotropic-nihility state, the conditions of
+branches merging of bulk polaritons, as well as an anomalous dispersion of bulk
+and surface polaritons are found and discussed.",1512.07870v2
+2019-07-08,Effect of elasto-plastic compatibility of grains on the void initiation criteria in low carbon steel,"The present study evidences the role of ferrite grain size distributions on
+the occurrence of void initiation in a low carbon steel. Various
+thermomechanical treatments were done to create ultrafine, bimodal and coarse
+range of ferrite grain distributions. A two parameter characterization of
+probable void initiation sites is proposed; elastic modulus difference and
+difference in Schmid factor of the grains surrounding the void. All
+microstructures were categorized based on the ability to ease or resist void
+nucleation. For coarse grains, elastic modulus difference as well as the Schmid
+factor difference is highest, intermediate for ultrafine and lowest for bimodal
+microstructure.",1907.03703v1
+2021-01-28,Prediction of new low-energy phases of BiFeO$_3$ with large unit cell and complex tilts beyond Glazer notation,"Bismuth ferrite is one of the most widely studied multiferroic materials
+because of its large ferroelectric polarisation coexisting with magnetic order
+at room temperature. Using density functional theory (DFT), we identify several
+previously unknown polar and non-polar structures within the low-energy phase
+space of perovskite-structure bismuth ferrite, BiFeO$_3$. Of particular
+interest is a series of non-centrosymmetric structures with polarisation along
+one lattice vector, combined with anti-polar distortions, reminiscent of
+ferroelectric domains, along a perpendicular direction. We discuss possible
+routes to stabilising the new phases using biaxial heteroepitaxial strain or
+interfacial electrostatic control in heterostructures.",2101.12114v1
+2019-03-22,Spin-wave coupling to electromagnetic cavity fields in dysposium ferrite,"Coupling of spin-waves with electromagnetic cavity field is demonstrated in
+an antiferromagnet, dysprosium ferrite (DyFeO3). By measuring transmission at
+0.2-0.35 THz and sweeping sample temperature, magnon-photon coupling signatures
+were found at crossings of spin-wave resonances with Fabry-Perot cavity modes
+formed in samples. The obtained spectra are explained in terms of classical
+electrodynamics and a microscopic model.",1903.09590v2
+2019-11-07,Magnetic monopoles and toroidal moments in LuFeO$_3$ and related compounds,"Magnetic monopoles and toroidal order are compelling features that have long
+been theorized but remain elusive in real materials. Multiferroic hexagonal
+ferrites are an interesting realization of frustrated triangular lattice, where
+magnetic order is coupled to ferroelectricity and trimerization. Here we
+propose a mechanism, through which magnetic monopolar and toroidal orders
+emerge from the combination of 120$^\circ$ antiferromagnetism and
+trimerization, present in hexagonal manganites and ferrites. The experimentally
+observable signatures of magnetic monopolar and toroidal orders are identified
+in the inelastic neutron scattering cross section, simulated from a microscopic
+model of LuFeO3. The non-reciprocal magnon propagation is demonstrated.",1911.02704v1
+2020-08-31,A collection of definitions and fundamentals for a design-oriented inductor model,"This paper defines and develops useful concepts related to the several kinds
+of inductances employed in any comprehensive design-oriented ferrite-based
+inductor model, which is required to properly design and control high-frequency
+operated electronic power converters. It is also shown how to extract the
+necessary parameters from a ferrite material datasheet in order to get inductor
+models useful for a wide range of core temperatures and magnetic induction
+levels.",2008.13634v3
+2004-01-24,Dielectric and Pyroelectric Properties of Thick Film Ferromagnetic - Piezoelectric Structures,"Layered ferromagnetic-piezoelectric composites show mechanical strain
+mediated electromagnetic coupling. Here we discuss dielectric and piezoelectric
+properties of ferrite-lead zirconate titanate (PZT) and lanthanum manganite-PZT
+samples. Results of our investigations on dielectric and pyroelectric
+properties of multilayer ferromagnetic-piezoelectric are presented here. Lead
+zircinate-titanate PbZrxTi1-xO3 (PZT) was used for the piezoelectric phase in
+all the structures. The following materials were used for the ferromagnetic
+component: nickel-zinc ferrites Ni0.9Zn 0.1Fe2O4 (NFO1) and Ni0.8Zn0.2Fe2O4
+(NFO2), cobalt ferrite (CFO), lithium ferrite (LFO), lanthanum strontium
+manganite La0.7Sr0.3MnO3 (LSM), and lanthanum-calcium manganite La0.7Ca0.3MnO3
+(LCM). The pyroelectric effect was studied by measuring the current J flowing
+through a closed loop containing the sample and an electrometer as the sample
+temperature T was slowly varied at the rate 0.1 K/s. Polarized PZT layers
+generate a pyroelectric current as the temperature changes. The main indicator
+of pyroelectric nature of the current is the sign reversal when the thermal
+cycle is switched from heating to cooling. Almost all of the multilayer
+structures showed a pyroelectric current, but the pyroelectric coefficient
+varied in a wide range. (i) For NFO1-PZT system the coefficient was in the
+range 0.01 - 10 nC/(cm2 K), depending on the temperature. (ii) CFO-PZT and
+LFO-PZT structures showed a large thermal current and a weak pyroelectric
+effect. (iii) Thermal currents, however, were absent in LCM-PZT within the
+temperature range from the room temperature to 400 K. (iv) In LSM-PZT, the
+thermal current exceeded the pyroelectric current. A model is proposed for an
+understanding of these results.",0401481v1
+2005-07-13,Colossal Spin-Phonon Anomalies and the Ferroelectric Phase Transition in the Model Multiferroic Bifeo3,"We report a temperature-dependent Raman and neutron scattering investigation
+of the multiferroic material bismuth ferrite BiFeO3 (BFO).",0507291v1
+2013-11-25,Structural and Dielectric Characterization on Multiferroic xNi0.9Zn0.1Fe2O4/(1-x)PbZr0.52Ti0.48O3 Particulate Composite,"We have carried out the powder x-ray diffraction and dielectric studies on
+multiferroic particulate composite xNi0.9Zn0.1Fe2O4/(1-x)PbZr0.52Ti0.48O3 with
+x=0.15, 0.30, 0.45, 0.60, 0.75 and 0.90 to explore the structural and
+ferroelectric properties. A conventional double sintering method was used to
+prepare the xNi0.9Zn0.1Fe2O4/(1-x)PbZr0.52Ti0.48O3 composites. The structure of
+one of the component Ni0.9Zn0.1Fe2O4 is spinel cubic with space group Fd3m,
+while the other component PbZr0.52Ti0.48O3 is selected around the morphotropic
+phase boundary region in which the tetragonal and monoclinic phases with space
+group P4mm and Cm coexist respectively. We have carried out Rietveld refinement
+of the structure to check the formation of ideal composites with separate
+ferroelectric and ferrite phases. Even though the structural characterization
+does not reveal the formation of any new phase due to reaction between the two
+components of the composite during sintering, the tetragonality of the
+PbZr0.52Ti0.48O3 continuously decreases with increasing the ferrite fraction
+while the lattice parameter of ferrite phase increases with increasing fraction
+of the ferroelectric phase. Similarly, the dielectric study reveals clear shift
+in the ferroelectric to paraelectric phase transition temperature of
+PbZr0.52Ti0.48O3 during composite formation suggesting that part of Ni2+, Zn2+/
+Fe3+ ions are diffusing at the B-site of PbZr0.52Ti0.48O3 replacing Ti4+, which
+in turn decreases its transition temperature. Scanning electron micrograph of
+sintered pellet surface confirms the presence of two types of particle
+morphology in the particulate composite, corresponding to ferrite and
+ferroelectric phases.",1311.6217v2
+2016-10-08,Enhancement of Impedance by Chromium Substitution and Correlation with DC Resistivity in Cobalt Ferrite,"Chromium substituted cobalt ferrite with grain size less than the single
+domain (approx. 70 nm) has been prepared by the sol-gel method. XRD analysis
+reveals that the samples crystallize to cubic symmetry with spacegroup number
+227. Two transition temperatures (TD (approx. 450 K) and TM (approx. 600 K)
+have been observed from the impedance verses temperature measurement. TD
+increases with the increase in frequency due to dipole response to the
+frequency. TM is comparable with the para-ferrimagnetic transition temperature
+of cobalt ferrite, which is independent of frequency. This result is well
+supported by the temperature dependent DC conductivity measurement. The
+modified Debye relaxation could be explained the impedance spectra of
+CoFe2-xCrxO4. The grain and grain boundary effect on impedance spectroscopy has
+been observed from Cole-Cole analysis. The ac conductivity follows Arrhenius
+behavior at different frequencies. All the samples exhibit the negative
+temperature coefficient of resistance behavior which reveals the semiconducting
+behavior of the material. The Mott VRH model could explain the DC electrical
+conductivity. Both ac impedance and DC resistivity are well co-related each
+other to explain the electron transport properties in Cr substituted cobalt
+ferrite. The electrical transport properties could be explained by the electron
+hopping between different metal ions via oxygen in the material.",1610.02489v1
+2020-07-01,"Impact of V substitution on the physical properties of Ni-Zn-Co ferrites: structural, magnetic, dielectric and electrical properties","We have investigated the Vanadium- (V) substituted Ni-Zn-Co ferrites where
+the samples were prepared using solid-state reaction technique. The impact of
+V5+ substitution on the structural, magnetic, dielectric and electrical
+properties of Ni-Zn-Co ferrites has been studied. XRD analysis confirmed the
+formation of a single-phase cubic spinel structure. The lattice constants have
+been calculated both theoretically and experimentally along with other
+structural parameters such as bulk density, X-ray density and porosity. The
+FESEM images are taken to study the surface morphology. FTIR measurement is
+also performed which confirms spinel structure formation. The saturation
+magnetization (Ms), coercive field (Hc) and Bohr magneton (B) were calculated
+from the obtained M-H loops. The temperature dependent permeability is studied
+to obtain the Curie temperature. Frequency and composition dependence of
+permeability was also analyzed. Dielectric behavior and ac resistivity are also
+subjected to investigate the frequency dependency. An inverse relationship was
+observed between the composition dependence of dielectric constant and ac
+resistivity. The obtained results such as the electrical resistivity,
+dielectric constants and magnetic properties suggest the appropriateness of the
+studied ferrites in microwave device applications.",2007.00602v1
+2019-10-30,Coherent x-ray radiation induced by high-current breakdown on a ferrite surface,"We for the first time observe that at the initial stage of a high-current
+discharge, a low-divergence short (< 2 ns) electromagnetic pulse is formed over
+a ferrite surface. The 50% part of this pulse lies in the region of fairly hard
+x-ray radiation (photon energy >1 keV) with the energy $\approx$0.6 mJ and the
+average power 0.3 MW. The radiation propagates parallel to the surface in the
+anode direction with the angle divergence < 2$^{o}$. The high directionality of
+the radiation in absence of the aperture-limiting devices for the radiation
+beam and the quadratic dependence of the spatial radiation energy flux density
+on the active part of the ferrite prism points to the coherent nature of the
+observed radiation. A possible generation mechanism of the radiation is
+proposed. It is based on the short-lived magnetization of the unit areas on the
+ferrite surface by a high-power electromagnetic pulse and subsequent coherent
+interference of the unit waves irradiated by these areas.",1910.13851v2
+2020-01-03,Synthesis and characterization of Zn doped Mn ferrites nanostructures,"Zn doped Mn ferrites nanoparticles were fabricated by using Co-precipitation.
+Variation in structure, magnetic and optical properties of MnZn ferrites has
+been discussed. First of all, samples were synthesized, annealed at different
+temperatures and then characterized. The as-synthesized and annealed samples
+were investigated by X-ray diffraction (XRD), Scanning electron microscopy
+(SEM), Energy Dispersive spectroscopy (EDX), Ultra Violet visible spectrometry
+(Uv-Vis spectrometry) and Vibrating sample magnetometer (VSM). The average
+crystallite size of MnZn ferrites nanoparticles determined from XRD were in the
+range of 42 to 60 nm. These nanoparticles possess normal spinel structure. The
+SEM images showed the physical shape of the samples, which showed that the as
+prepared samples are more agglomerated and having flake like shape rather than
+annealed at 700C while the samples have longitudinal or rod like shape on
+annealing at 700C. The coercivity (Hc), saturation magnetization (Ms), and
+remanence (Mr) of Nps were also calculated. The (Ms) value is increasing from
+26 to 65 emu/g, the coercivity (Hc) is varying from 13 to 193 Oe and remanence
+(Mr) has also showing increasing trend although very less, from 0.031 to 0.798
+emu/g which are a little part of their bulk counter parts. The band gap energy
+of the samples was showing decreasing trend as with the increase of particle
+size which is of the order of 3.5 to 2.9 eV.",2001.00741v1
+2020-09-17,Magnetoelectric near fields,"We consider near field topological singularities originated from magnetic
+dipolar mode oscillations in ferrite disk particles.",2009.08084v1
+2022-11-02,Solar energy harvesting in magnetoelectric coupled manganese ferrite nanoparticles incorporated nanocomposite polymer films,"Poly(vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE)) based
+pyroelectric as well as magnetoelectric materials offer great promises for
+energy harvesting for flexible and wearable applications. Hence, this work
+focus on solar energy harvesting as well as magnetoelectric phenomenon in two
+phase nanocomposite film where the constituting phases are manganese ferrite
+(MnFe2O4) nanoparticles and P(VDF-TrFE) polymer. Composite films have been
+prepared using solution casting technique. X-ray diffraction result shows
+higher crystallinity of these films. The ferroelectric, magnetic and
+magnetoelectric properties in variation with applied field and volume
+percentage of ferrite nanoparticles have been investigated. The preparation
+condition was optimized in such a way that it results improved ferroelectric
+polarization of nanocomposite film after incorporation of small amount of
+ferrite nanoparticles. The maximum magnetoelectric-coupling coefficient of
+about 156 mV/Oe-Cm was obtained for optimum nanocomposite film when DC bias
+field was applied perpendicular to electric polarization direction. From a
+pyroelectric device perspective, solar energy harvesting is also reported. An
+open circuit voltage of 5V and short circuit current of order of ~1 nA is
+demonstrated without any pre amplification. Hence, the combination of
+magnetoelectric and pyroelectric properties of nanocomposite film presented
+here indicate as a perfect candidate for smart materials, spintronics devices
+and specified magnetoelectric-based applications.",2211.01007v2
+2023-03-30,Towards Quantitative Analysis of Deuterium Absorption in Ferrite and Austenite during Electrochemical Charging by Comparing Cyclic Voltammetry and Cryogenic Transfer Atom Probe Tomography,"Hydrogen embrittlement mechanisms of steels have been studied for several
+decades. Understanding hydrogen diffusion behavior in steels is crucial towards
+both developing predictive models for hydrogen embrittlement and identifying
+mitigation strategies. However, because hydrogen has a low atomic mass, it is
+extremely challenging to detect by most analytical methods. In recent years,
+cryogenic-transfer atom probe tomography (APT) of
+electrochemically-deuterium-charged steels has provided invaluable qualitative
+analysis of nanoscale deuterium traps such as carbides, dislocations, grain
+boundaries and interfaces between ferrite and cementite. Independently, cyclic
+voltammetry (CV) has provided valuable analysis of bulk hydrogen diffusion in
+steels. In this work, we use a combination of CV and cryogenic-transfer APT for
+quantitative analysis of deuterium pickup in electrolytically charged pure Fe
+(ferrite) and a model austenitic Fe18Cr14Ni alloy without any second phase or
+defect trap sites. The high solubility and low diffusivity of hydrogen in
+austenite versus ferrite are highlighted to result in clear observable
+signatures in CV and cryogenic-transfer APT results. The remaining challenges
+and pathway for enabling quantitative analysis of hydrogen pick up in steels is
+also discussed.",2303.17070v1
+2023-09-24,FeCo Nanowire-Strontium Ferrite Powder Composites for Permanent Magnets with High-Energy Products,"Due to the issues associated with rare-earth elements, there arises a strong
+need for magnets with properties between those of ferrites and rare-earth
+magnets that could substitute the latter in selected applications. Here, we
+produce a high remanent magnetization composite bonded magnet by mixing FeCo
+nanowire powders with hexaferrite particles. In the first step, metallic
+nanowires with diameters between 30 and 100 nm and length of at least 2 {\mu}m
+are fabricated by electrodeposition. The oriented as-synthesized nanowires show
+remanence ratios above 0.76 and coercivities above 199 kA/m and resist core
+oxidation up to 300 {\deg}C due to the existence of a > 8 nm thin oxide
+passivating shell. In the second step, a composite powder is fabricated by
+mixing the nanowires with hexaferrite particles. After the optimal nanowire
+diameter and composite composition are selected, a bonded magnet is produced.
+The resulting magnet presents a 20% increase in remanence and an enhancement of
+the energy product of 48% with respect to a pure hexaferrite (strontium
+ferrite) magnet. These results put nanowire-ferrite composites at the forefront
+as candidate materials for alternative magnets for substitution of rare earths
+in applications that operate with moderate magnet performance.",2309.13724v1
+2024-02-21,Discrete slip plane analysis of ferrite microtensile tests: On the influence of dislocation source distribution and non-Schmid effects on slip system activity,"The slip system activity in microtensile tests of ferrite single crystals is
+compared with predictions made by the discrete slip plane model proposed by
+Wijnen et al. (International Journal of Solids and Structures 228, 111094,
+2021). This is an extension of conventional crystal plasticity in which the
+stochastics and physics of dislocation sources are taken into account in a
+discrete slip band. This results in discrete slip traces and non-deterministic
+mechanical behavior, similar to what is observed in experiments. A detailed
+analysis of which slip systems are presumed to be active in experiments is
+performed. In small-scale mechanical tests on BCC metals and alloys, non-Schmid
+effects are often needed to explain the observed response. Therefore, these
+effects are incorporated into the model by extending a non-Schmid framework
+commonly used to model {110} slip to {112} planes. The slip activity in the
+simulations is compared to the slip activity in single crystal ferrite
+microtensile tests. This is done for the discrete slip plane model with and
+without non-Schmid effects, as well as for a conventional crystal plasticity
+model. The conventional crystal plasticity model fails to predict the diversity
+in active slip systems that is observed experimentally. The slip activity
+obtained with the discrete slip plane model is in convincingly better agreement
+with the experiments. Including non-Schmid effects only entails minor
+differences. This suggests that stochastic effects dominate the behavior of
+ferrite crystals with dimensions in the order of a few micrometers and that
+non-Schmid effects may not play a large role.",2402.14168v1
+2003-07-23,Dynamic Magnetoelectric Effects in Bulk and Layered composites of Cobalt Zinc Ferrite and Lead Zirconate Titanate,"Low frequency magnetoelectric (ME) coupling has been investigated in bulk and
+multilayers of cobalt zinc ferrite, Co1-xZnxFe2O4 (x=0-0.6), and lead zirconate
+titanate. In bulk samples, the transverse and longitudinal couplings are weak
+and are of equal magnitude. A substantial strengthening of ME interactions is
+evident in layered structures, with the ME voltage coefficient a factor of
+10-30 higher than in bulk samples. Important findings of the studies in layered
+composites are as follows. (i) The transverse coupling is stronger than the
+longitudinal coupling. (ii) The strength of ME interactions is dependent on Zn
+substitution with a maximum for x=0.4. (iii) Analysis of volume and static
+magnetic field dependence of ME voltage coefficients reveal a weak coupling at
+the ferromagnetic-piezoelectric interface. (iv) The interface coupling k
+increases with Zn substitution and k versus x profile shows a maximum centered
+at x=0.4. (iv) The Zn-assisted enhancement is attributed to efficient
+magneto-mechanical coupling in the ferrite.",0307597v1
+2006-06-24,Synthesis and Magnetic Properties of Cobalt Ferrite (CoFe2O4) Nanoparticles Prepared by Wet Chemical Route,"Magnetic nanoparticles of cobalt ferrite have been synthesized by wet
+chemical method using stable ferric and cobalt salts with oleic acid as the
+surfactant. X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM)
+confirmed the formation of single phase cobalt ferrite nanoparticles in the
+range 15-48nm depending on the annealing temperature and time. The size of the
+particles increases with annealing temperature and time while the coercivity
+goes through a maximum, peaking at around 28nm. A very large coercivity
+(10.5kOe) is observed on cooling down to 77K while typical blocking effects are
+observed below about 260K. The high field moment is observed to be small for
+smaller particles and approaches the bulk value for large particles.",0606631v2
+2006-07-03,Interaction between superconducting vortices and Bloch wall in ferrite garnet film,"Interaction between a Bloch wall in a ferrite-garnet film and a vortex in a
+superconductor is analyzed in the London approximation. Equilibrium
+distribution of vortices formed around the Bloch wall is calculated. The
+results agree quantitatively with magneto-optical experiment where an in-plane
+magnetized ferrite-garnet film placed on top of NbSe2 superconductor allows
+observation of individual vortices. In particular, our model can reproduce a
+counter-intuitive attraction observed between vortices and a Bloch wall having
+the opposite polarity. It is explained by magnetic charges appearing due to
+discontinuity of the in-plane magnetization across the wall.",0607043v2
+2007-02-14,Vortices and chirality of magnetostatic modes in quasi-2D ferrite disk particles,"In this paper we show that the vortex states can be created not only in
+magnetically soft ""small"" (with the dipolar and exchange energy competition)
+cylindrical dots, but also in magnetically saturated ""big"" (when the exchange
+is neglected) cylindrical dots. A property associated with a vortex structure
+becomes evident from an analysis of confinement phenomena of magnetic
+oscillations in a ferrite disk with a dominating role of magnetic-dipolar
+(non-exchange-interaction) spectra. In this case the scalar
+(magnetostatic-potential) wave functions may have a phase singularity in a
+center of a dot. A non-zero azimuth component of the flow velocity demonstrates
+the vortex structure. The vortices are guaranteed by the chiral edge states of
+magnetic-dipolar modes in a quasi-2D ferrite disk.",0702327v1
+2007-03-11,A low-noise ferrite magnetic shield,"Ferrite materials provide magnetic shielding performance similar to commonly
+used high permeability metals but have lower intrinsic magnetic noise generated
+by thermal Johnson currents due to their high electrical resistivity.
+Measurements inside a ferrite shield with a spin-exchange relaxation-free
+atomic magnetometer reveal a noise level of 0.75 fT Hz^(-1/2), 25 times lower
+than what would be expected in a comparable mu-metal shield. The authors
+identify a 1/f component of the magnetic noise due to magnetization
+fluctuations and derive general relationships for the Johnson current noise and
+magnetization noise in cylindrical ferromagnetic shields in terms of their
+conductivity and complex magnetic permeability.",0703115v2
+2007-07-09,"Effective chiral magnetic currents, topological magnetic charges, and microwave vortices in a cavity with an enclosed ferrite disk","In microwaves, a TE-polarized rectangular-waveguide resonator with an
+inserted thin ferrite disk gives an example of a nonintegrable system. The
+interplay of reflection and transmission at the disk interfaces together with
+the material gyrotropy effect gives rise to whirlpool-like electromagnetic
+vortices in the proximity of the ferromagnetic resonance. Based on numerical
+simulation, we show that a character of microwave vortices in a cavity can be
+analyzed by means of consideration of equivalent magnetic currents. Maxwell
+equations allows introduction of a magnetic current as a source of the
+electromagnetic field. Specifically, we found that in such nonintegrable
+structures, magnetic gyrotropy and geometrical factors leads to the effect of
+symmetry breaking resulting in effective chiral magnetic currents and
+topological magnetic charges. As an intriguing fact, one can observe precessing
+behavior of the electric-dipole polarization inside a ferrite disk.",0707.1216v1
+2007-07-09,Microwave whirlpools in a rectangular-waveguide cavity with a thin ferrite disk,"We study a three dimensional system of a rectangular-waveguide resonator with
+an inserted thin ferrite disk. The interplay of reflection and transmission at
+the disk interfaces together with material gyrotropy effect, gives rise to a
+rich variety of wave phenomena. We analyze the wave propagation based on full
+Maxwell-equation numerical solutions of the problem. We show that the
+power-flow lines of the microwave-cavity field interacting with a ferrite disk,
+in the proximity of its ferromagnetic resonance, form whirlpool-like
+electromagnetic vortices. Such vortices are characterized by the dynamical
+symmetry breaking. The role of ohmic losses in waveguide walls and dielectric
+and magnetic losses in a disk is a subject of our investigations.",0707.1236v1
+2008-04-10,Eigen power-flow-density vortices of magnetostatic modes in thin ferrite disks,"In confined magnetically ordered structures one can observe vortices of
+magnetization and electromagnetic power flow vortices. There are topologically
+distinct and robust states. In this paper we show that in a normally magnetized
+quasi-2D ferrite disk there exist eigen power-flow-density vortices of
+magnetic-dipolar-mode oscillations. Because of such circular power flows, the
+oscillating modes are characterized by stable magnetostatic energy states and
+discrete angular moments of the wave fields. We show that the
+power-flow-density vortices of magnetostatic modes can be excited by
+electromagnetic fields of a microwave cavity. There is a clear correspondence
+between the power-flow-density vortex structures in a ferrite disk derived from
+an analytical solution of the magnetostatic-wave spectral problem and obtained
+by the numerical-simulation electromagnetic program.",0804.1666v1
+2009-08-24,"Spinel ferrite nanocrystals embedded inside ZnO: magnetic, electronic and magneto-transport properties","In this paper we show that spinel ferrite nanocrystals (NiFe2O4, and CoFe2O4)
+can be texturally embedded inside a ZnO matrix by ion implantation and
+post-annealing. The two kinds of ferrites show different magnetic properties,
+e.g. coercivity and magnetization. Anomalous Hall effect and positive
+magnetoresistance have been observed. Our study suggests a
+ferrimagnet/semiconductor hybrid system for potential applications in
+magneto-electronics. This hybrid system can be tuned by selecting different
+transition metal ions (from Mn to Zn) to obtain various magnetic and electronic
+properties.",0908.3488v1
+2009-11-22,Electronic structure and magnetic properties of Ni0.2Cd0.3Fe2.5-xAlxO4 (x = 0.0 - 0.4) ferrite nanoparticles,"Structural, magnetic and electronic structural properties of
+Ni0.2Cd0.3Fe2.5-xAlxO4 ferrites nanoparticles have been studied x-ray
+diffraction (XRD), transmission electron microscopy (TEM), dc magnetization,
+and near edge x-ray absorption fine structure spectroscopy (NEXAFS)
+measurements. Nanoparticles of Ni0.2Cd0.3Fe2.5-xAlxO4 (x = 0.0 - 0.4) ferrite
+were synthesized using sol-gel method. The XRD and TEM measurements show that
+all samples have single phase nature with cubic structure and have
+nanocrystalline behavior. From the XRD and TEM analysis, it is observed that
+particle size increases with Al doping. DC magnetization measurements infer
+that magnetic moment decreases whereas blocking temperature increases with
+increase in Al doping. It is observed that the magnetic moment decreases with
+Al doping which may be due to the dilution of the sublattice by the doping of
+Al ions. The NEXAFS measurements performed at room temperature indicates that
+Fe exist in mixed valence state.",0911.4227v1
+2010-06-07,A Robust Approach for the Growth of Epitaxial Spinel Ferrite Films,"Heteroepitaxial spinel ferrites NiFe2O4 and CoFe2O4 films have been prepared
+by pulsed laser deposition (PLD) at various temperatures (175 - 690 {\deg}C)
+under ozone/oxygen pressure of 10 mTorr. Due to enhanced kinetic energy of
+ablated species at low pressure and enhanced oxidation power of ozone, epitaxy
+has been achieved at significantly lower temperatures than previously reported.
+Films grown at temperature below 550 {\deg}C show a novel growth mode, which we
+term ""vertical step-flow"" growth mode. Epitaxial spinel ferrite films with
+atomically flat surface over large areas and enhanced magnetic moment can be
+routinely obtained. Interestingly, the growth mode is independent of the nature
+of substrates (spinel MgAl2O4, perovskite SrTiO3, and rock salt MgO) and film
+thicknesses. The underlying growth mechanism is discussed.",1006.1161v1
+2011-02-21,Contributions of Al and Ni segregation to the interfacial cohesion of Cu-rich precipitates in ferritic steels,"We characterise the influence of the segregation behaviours of two typical
+alloying elements, aluminium and nickel, on the interfacial cohesive properties
+of copper-rich precipitates in ferritic steels, with a view towards
+understanding steel embrittlement. The first-principles method is used to
+compute the energetic and bonding properties of aluminium and nickel at the
+interfaces of the precipitates and corresponding fracture surfaces. Our results
+show the segregation of aluminium and nickel at interfaces of precipitates are
+both energetically favourable. We find that the interfacial cohesion of copper
+precipitates is enhanced by aluminium segregation but reduced by nickel
+segregation. Opposite roles can be attributed to the different symmetrical
+features of the valence states for aluminium and nickel. The nickel-induced
+interfacial embrittlement of copper-rich precipitates increase the
+ductile-brittle transition temperature (DBTT) of ferritic steels and provides
+an explanation of many experimental phenomena, such as the fact that the shifts
+of DBTT of reactor pressure vessel steels depend the copper and nickel content.",1102.4234v2
+2011-03-29,Probing Magnetoelastic Coupling and Structural Changes in Magnetoelectric Gallium Ferrite,"Temperature dependent X-ray diffraction and Raman spectroscopic studies were
+carried out on the flux grown single crystals of gallium ferrite with Ga:Fe
+ratio of 0.9:1.1. Site occupancy calculations from the Rietveld refinement of
+the X-ray data led to the estimated magnetic moment of ~0.60 \muB /f.u. which
+was in good agreement with the experimental data. Combination of these two
+measurements indicates that there is no structural phase transition in the
+material between 18 K to 700 K. A detailed line shape analysis of the Raman
+mode at ~375 cm^-1 revealed a discontinuity in the peak position data
+indicating the presence of spin-phonon coupling in gallium ferrite. A
+correlation of the peak frequency with the magnetization data led to two
+distinct regions across a temperature ~180 K with appreciable change in the
+spin-phonon coupling strength from ~ 0.9 cm^-1 (T < 180 K) to 0.12 cm-1 (180 K
+< T < Tc). This abrupt change in the coupling strength at ~180 K strongly
+suggests an altered spin dynamics across this temperature.",1103.5541v2
+2011-03-30,Analysis of volume distribution of power loss in ferrite cores,"We present a technique to estimate the inhomogeneities of magnetic loss
+across the section of ferrite cores under ac excitation. The technique is based
+on two distinct calorimetric methods that we presented elsewhere. Both methods
+are based on the measurement of the rate of increase of the sample temperature
+under adiabatic condition. The temperature ramp is recorded either measuring
+the sample bulk resistivity or using a platinum probe pasted on the sample
+surface. As an example we apply the procedure to an industrial sample of Mn-Zn
+ferrite under controlled sinusoidal excitation with a peak induction of 50 mT
+in the range between 100 kHz and 2 MHz. The results are discussed by comparison
+with simulations of the dissipation field profile through the sample,
+calculated using a finite element method (FEM) code.",1103.5839v1
+2011-06-07,Effect of Zn substitution on morphology and magnetic properties of copper ferrite nanofibers,"Spinel ferrite Cu1-xZnxFe2O4 nanofibers over a compositional range 0 < x < 1
+were prepared by electrospinning combined with sol-gel method. The influence of
+Zn2+ ions substitution on morphology, structure, and magnetic properties of
+copper ferrite has been investigated. The results show that surface of CuFe2O4
+nanofibers consists of small open porosity, while surface of doped nanofibers
+reveals smooth and densified nature. With increasing Zn substitution,
+saturation magnetization initially increases and then decreases with a maximum
+value of 58.4 emu/g at x = 0.4, coercivity and square ratio all decrease. The
+influence of substitution on magnetic properties is related with the cation
+distraction and exchange interactions between spinel lattices.",1106.1269v1
+2011-08-11,Thermoelectric Spin-Transfer Torque MRAM with Sub-Nanosecond Bi-Directional Writing using Magnonic Current,"A new genre of Spin-Transfer Torque (STT) MRAM is proposed, in which
+bi-directional writing is achieved using thermoelectrically controlled magnonic
+current as an alternative to conventional electric current. The device uses a
+magnetic tunnel junction (MTJ), which is adjacent to a non-magnetic metallic
+and a ferrite film. This film stack is heated or cooled by a Peltier element
+which creates a bi-directional magnonic pulse in the ferrite film. Conversion
+of magnons to spin current occurs at the ferrite-metal interface, and the
+resulting spin-transfer torque is used to achieve sub-nanosecond precessional
+switching of the ferromagnetic free layer in the MTJ. Compared to electric
+current driven STT-MRAM with perpendicular magnetic anisotropy (PMA),
+thermoelectric STT-MRAM reduces the overall magnetization switching energy by
+more than 40% for nano-second switching, combined with a write error rate (WER)
+of less than 10-9 and a lifetime of 10 years or higher. The combination of
+higher thermal activation energy, sub-nanosecond read/write speed, improved
+tunneling magneto-resistance (TMR) and tunnel barrier reliability make
+thermoelectric STT-MRAM a promising choice for future non-volatile memory
+applications.",1108.2386v1
+2012-03-10,Room temperature ferromagnetism and giant permittivity in chemical routed Co1.5Fe1.5O4 ferrite particles and their composite with NaNO3,"We report structural, magnetic and dielectric properties of Co1.5Fe1.5O4
+nanoparticles and their composites with non-magnetic NaNO3. The samples were
+derived from metal nitrates solution at different pH values. The chemical
+routed sample was air heated at 200 0C and 500 0C. Heating of the material
+showed unusual decrease of crystallite size, but cubic spinel structure is seen
+in all samples. The samples of Co1.5Fe1.5O4 showed substantially large room
+temperature ferromagnetic moment, electrical conductivity, dielectric constant,
+and low dielectric loss. The samples are soft ferromagnet and electrically
+highly polarized. The interfaces of grains and grain boundaries are actively
+participating to determine the magnetic and dielectric properties of the
+ferrite grains. The effects of interfacial contribution are better realized
+using the ferrite and NaNO3 composite samples. We have examined different
+scopes of modifying the magnetic and dielectric parameters using same material
+in pure and composite form.",1203.2944v1
+2012-10-01,"Effect of Site-disorder, Off-stoichiometry and Epitaxial Strain on the Optical Properties of Magnetoelectric Gallium Ferrite","We present a combined experimental-theoretical study demonstrating the role
+of site disorder, off-stoichiometry and strain on the optical behavior of
+magnetoelectric gallium ferrite. Optical properties such as band-gap,
+refractive indices and dielectric constants were experimentally obtained by
+performing ellipsometric studies over the energy range 0.8 eV to 4.2 eV on
+pulsed laser deposited epitaxial thin films of stoichiometric gallium ferrite
+with b-axis orientation and the data was compared with theoretical results.
+Calculations on the ground state structure show that the optical activity in
+GaFeO3 arises primarily from O2p-Fe3d transitions. Further, inclusion of site
+disorder and epitaxial strain in the ground state structure significantly
+improves the agreement between the theory and the room temperature experimental
+data substantiating the presence of site-disorder in the experimentally derived
+strained GaFeO3 films at room temperature. We attribute the modification of the
+ground state optical behavior upon inclusion of site disorder to the
+corresponding changes in the electronic band structure, especially in Fe3d
+states leading to a lowered band-gap of the material.",1210.0356v1
+2015-02-21,On-chip superconducting microwave circulator from synthetic rotation,"We analyze the design of a potential replacement technology for the
+commercial ferrite circulators that are ubiquitous in contemporary quantum
+superconducting microwave experiments. The lossless, lumped element design is
+capable of being integrated on chip with other superconducting microwave
+devices, thus circumventing the many performance-limiting aspects of ferrite
+circulators. The design is based on the dynamic modulation of DC
+superconducting microwave quantum interference devices (SQUIDs) that function
+as nearly linear, tunable inductors. The connection to familiar ferrite-based
+circulators is a simple frame boost in the internal dynamics' equation of
+motion. In addition to the general, schematic analysis, we also give an
+overview of many considerations necessary to achieve a practical design with a
+tunable center frequency in the 4-8 GHz frequency band, a bandwidth of 240 MHz,
+reflections at the -20 dB level, and a maximum signal power of approximately
+order 100 microwave photons per inverse bandwidth.",1502.06041v1
+2015-04-14,Magnetic charges and magnetoelectricity in hexagonal rare-earth manganites and ferrites,"Magnetoelectric (ME) materials are of fundamental interest and show broad
+potential for technological applications. Commonly the dominant contribution to
+the ME response is the lattice-mediated one, which is proportional to both the
+Born electric charge $Z^{\rm e}$ and its analogue, the dynamical magnetic
+charge $Z^{\rm m}$. Our previous study has shown that exchange striction acting
+on noncollinear spins induces much larger magnetic charges than those that
+depend on spin-orbit coupling. The hexagonal manganites $R$MnO$_3$ and ferrites
+$R$FeO$_3$ ($R$ = Sc, Y, In, Ho-Lu) exhibit strong couplings between electric,
+magnetic and structural degrees of freedom, with the transition-metal ions in
+the basal plane antiferromagnetically coupled through super-exchange so as to
+form a 120$^\circ$ noncollinear spin arrangement. Here we present a theoretical
+study of the magnetic charges, and of the spin-lattice and spin-electronic ME
+constants, in these hexagonal manganites and ferrites, clarifying the
+conditions under which exchange striction leads to an enhanced $Z^{\rm m}$
+values and anomalously large in-plane spin-lattice ME effects.",1504.03405v1
+2015-10-20,First-principles investigation of boron defects in nickel ferrite spinel,"The accumulation of boron within the porous nickel ferrite (NiFe2O4, NFO)
+deposited on fuel rods is a major technological problem with important safety
+and economical implications. In this work the electronic structure of nickel
+ferrite is investigated using first-principles methods, and the results are
+combined with experimental data to analyze B incorporation into the NFO
+structure. Under thermodynamic equilibrium the calculations predict that the
+incorporation of B into the NFO structure is unfavorable. The main limiting
+factors are the narrow stability domain of NFO and the precipitation of B2O3,
+Fe3BO5, and Ni3B2O6 as secondary phases. In n-type NFO, the most stable defect
+is Ni vacancy while in p-type material lowest the formation energy belongs to
+tetrahedrally coordinated interstitial B . Because of these limiting conditions
+it is more thermodynamically favorable for B to form secondary phases with Fe,
+Ni and O than it is to form point defects in NFO",1510.05888v1
+2016-07-08,Easy axis orientation of Strontium ferrite thin films described by spin reorientation,"In plane orientation of magnetic easy axis of sputtered strontium hexaferrite
+thin films has been explained using classical Heisenberg Hamiltonian. The
+variation of average value of in plane spin component with temperature was
+plotted in order to determine the temperature at which easy axis is oriented in
+the plane of the strontium ferrite film. The average value of in plane spin
+component in this 2-D model reaches zero at one particular temperature. This
+particular temperature obtained using our theoretical model agrees with the
+experimental value of the temperature of rf sputtered polycrystalline strontium
+ferrite thin films deposited on polycrystalline Al2O3 substrates (500 0C). This
+spin reorientation temperature solely depends on the values of energy
+parameters used in our modified Heisenberg Hamiltonian equation.",1607.02327v1
+2017-03-31,Spin Seebeck effect in Y-type hexagonal ferrite thin films,"Spin Seebeck effect (SSE) has been investigated in thin films of two
+Y-hexagonal ferrites Ba$_2$Zn$_{2}$Fe$_{12}$O$_{22}$ (Zn2Y) and
+Ba$_2$Co$_{2}$Fe$_{12}$O$_{22}$ (Co2Y) deposited by a spin-coating method on
+SrTiO$_3$(111) substrate. The selected hexagonal ferrites are both
+ferrimagnetic with similar magnetic moments at room temperature and both
+exhibit easy magnetization plane normal to $c$-axis. Despite that, SSE signal
+was only observed for Zn2Y, whereas no significant SSE signal was detected for
+Co2Y. We tentatively explain this different behavior by a presence of two
+different magnetic ions in Co2Y, whose random distribution over octahedral
+sites interferes the long range ordering and enhances the Gilbert damping
+constant. The temperature dependence of SSE for Zn2Y was measured and analyzed
+with regard to the heat flux and temperature gradient relevant to the SSE
+signal.",1703.10903v1
+2017-04-08,Effect of annealing temperatures on the electrical conductivity and dielectric properties of Ni1.5Fe1.5O4 spinel ferrite prepared by chemical reaction at different pH values,"The electrical conductivity and dielectric properties of Ni1.5Fe1.5O4 ferrite
+has been controlled by varying the annealing temperature of the chemical routed
+samples. The frequency activated conductivity obeyed Jonschers power law and
+universal scaling suggested semiconductor nature. An unusual metal like state
+has been revealed in the measurement temperature scale in between two
+semiconductor states with different activation energy. The metal like state has
+been affected by thermal annealing of the material. The analysis of electrical
+impedance and modulus spectra has confirmed non-Debye dielectric relaxation
+with contributions from grains and grain boundaries. The dielectric relaxation
+process is thermally activated in terms of measurement temperature and
+annealing temperature of the samples. The hole hopping process, due to presence
+of Ni3+ ions in the present Ni rich ferrite, played a significant role in
+determining the thermal activated conduction mechanism. This work has
+successfully applied the technique of a combined variation of annealing
+temperature and pH value during chemical reaction for tuning electrical
+parameters in a wide range; for example dc limit of conductivity 10power(-4)
+-10power(-12) S/cm, and unusually high activation energy 0.17-1.36 eV.",1704.02495v2
+2018-05-04,The effect of the misfit dislocation on the in-plane shear response of the ferrite/cementite interface,"Although the pearlitic steel is one of the most extensively studied
+materials, there are still questions unanswered about the interface in the
+lamellar structure. In particular, to deepen the understanding of the
+mechanical behavior of pearlitic steel with fine lamellar structure, it is
+essential to reveal the structure-property relationship of the
+ferrite/cementite interface (FCI). In this study, we analyzed the in-plane
+shear deformation of the FCI using atomistic simulation combined with extended
+atomically informed Frank-Bilby (xAIFB) method and disregistry analyses. In the
+atomistic simulation, we applied in-plane shear stress along twelve different
+directions to the ferrite/cementite bilayer for Isaichev (IS), Near Bagaryatsky
+(Near BA) and Near Pitsch-Petch (Near PP) orientation relationship (OR),
+respectively. The simulation results reveal that IS and Near BA ORs show
+dislocation-mediated plasticity except two directions, while Near PP OR shows
+mode II (in-plane shear) fracture at the FCI along all directions. Based on the
+xAIFB and disregistry analysis results, we conclude that the in-plane shear
+behavior of the FCI is governed by the magnitude of Burgers vector and
+core-width of misfit dislocations.",1805.01591v1
+2011-11-18,Microwave near-field helicity and its role in the matter-field interaction,"In the preceding paper, we have shown analytically that in a source-free
+subwavelength region of microwave fields there exist the field structures with
+local coupling between the time-varying electric and magnetic fields differing
+from the electric-magnetic coupling in regular free-space electromagnetic
+waves. As a source of such near fields, there is a small quasi-2D ferrite disk
+with the magnetic-dipolar-mode (MDM) spectra. The near fields originated from a
+MDM ferrite particle are characterized by topologically distinctive structures
+of power-flow vortices, non-zero helicity, and a torsion degree of freedom. In
+this paper, we present numerical and experimental studies on the microwave
+near-field helicity and its role in the matter-field interaction. We show that
+one can distinguish different microwave near-field-helicity parameters for
+different permittivities of dielectric samples loading a ferrite-disk sensor.
+We analyze a role of topological structures of the fields on the helicity
+properties. We demonstrate dependence of the MDM spectra and the
+near-field-helicity parameters from the enantiomeric properties of the loading
+samples.",1111.4361v1
+2011-11-23,Magnetic and structural characterization of nanosized BaCo_xZn_{2-x}Fe_{16}O_{27} hexaferrite in the vicinity of spin reorientation transition,"Numerous applications of hexagonal ferrites are related to their easy axis or
+easy plane magnetocrystalline anisotropy configurations. Certain W-type
+ferrites undergo spin reorientation transitions (SRT) between different
+anisotropy states on magnetic field or temperature variation. The transition
+point can be tuned by modifying the chemical composition, which suggests a
+potential application of hexaferrites in room temperature magnetic
+refrigeration. Here we present the results of structural and magnetic
+characterization of BaCo_xZn_{2-x}Fe_{16}O_{27} (0.7 \leq x \leq 2) doped
+barium ferrites. Fine powders were prepared using a sol-gel citrate precursor
+method. Crystal structures and particle size distributions were examined by
+X-ray diffraction and transmission electron microscopy. The optimal synthesis
+temperature ensuring complete formation of single W-phase with limited grain
+growth has been determined. Spin reorientation transitions were revealed by
+thermomagnetic analysis and AC susceptibility measurements.",1111.5453v1
+2011-12-30,Large magnetic circular dichroism in resonant inelastic x-ray scattering at the Mn L-edge of Mn-Zn ferrite,"We report resonant inelastic x-ray scattering (RIXS) excited by circularly
+polarized x-rays on Mn-Zn ferrite at the Mn L2,3-resonances. We demonstrate
+that crystal field excitations, as expected for localized systems, dominate the
+RIXS spectra and thus their dichroic asymmetry cannot be interpreted in terms
+of spin-resolved partial density of states, which has been the standard
+approach for RIXS dichroism. We observe large dichroic RIXS at the L2-resonance
+which we attribute to the absence of metallic core hole screening in the
+insulating Mn-ferrite. On the other hand, reduced L3-RIXS dichroism is
+interpreted as an effect of longer scattering time that enables spin-lattice
+core hole relaxation via magnons and phonons occurring on a femtosecond time
+scale.",1201.0091v1
+2018-01-24,Quantization of magnetoelectric fields,"The effect of quantum coherence involving macroscopic degree of freedom, and
+occurring in systems far larger than individual atoms are one of the topical
+fields in modern physics. Because of material dispersion, a phenomenological
+approach to macroscopic quantum electrodynamics, where no canonical formulation
+is attempted, is used. The problem becomes more complicated when geometrical
+forms of a material structure have to be taken into consideration. Magnetic
+dipolar mode (MDM) oscillations in a magnetically saturated quasi 2D ferrite
+disk are macroscopically quantized states. In this ferrimagnetic structure,
+long range dipole dipole correlation in positions of electron spins can be
+treated in terms of collective excitations of a system as a whole. The near
+fields in the proximity of a MDM ferrite disk have space and time symmetry
+breakings. Such MDM-originated fields, called magnetoelectric (ME) fields,carry
+both spin and orbital angular momentums. By virtue of unique topology, ME
+fields are different from free space electromagnetic (EM) fields. The ME fields
+are quantum fluctuations in vacuum. We call these quantized states ME photons.
+There are not virtual EM photons. We show that energy, spin and orbital angular
+momenta of MDM oscillations constitute the key physical quantities that
+characterize the ME field configurations. We show that vacuum can induce a
+Casimir torque between a MDM ferrite disk, metal walls, and dielectric samples.",1801.08042v1
+2018-10-24,Electronic and optical properties of spinel zinc ferrite: $Ab$ $initio$ hybrid functional calculations,"Spinel ferrites in general show a rich interplay of structural, electronic,
+and magnetic properties. Here, we particularly focus on zinc ferrite (ZFO),
+which has been observed experimentally to crystallise in the cubic $normal$
+spinel structure. However, its magnetic ground state is still under dispute. In
+addition, some unusual magnetic properties in ZFO thin films or nanostructures
+have been explained by a possible partial cation inversion and a different
+magnetic interaction between the two cation sublattices of the spinel structure
+compared to the crystalline bulk material. Here, density functional theory has
+been applied to investigate the influence of different inversion degrees and
+magnetic couplings among the cation sublattices on the structural, electronic,
+magnetic, and optical properties. Effects of exchange and correlation have been
+modelled using the generalised gradient approximation (GGA) together with the
+Hubbard `+$U$' parameter, and the more elaborate hybrid functional PBE0. While
+the GGA+$U$ calculations yield an antiferromagnetically coupled $normal$ spinel
+structure as the ground state, in the PBE0 calculations the ferromagnetically
+coupled $normal$ spinel is energetically slightly favoured, and the hybrid
+functional calculations perform much better with respect to structural,
+electronic and optical properties.",1810.10555v1
+2019-07-30,The effect of heating rate and soaking time on microstructure of an advanced high strength steel,"This work focuses on the effect of soaking time on the microstructure during
+ultrafast heat treatment of a 50% cold rolled low carbon steel with initial
+ferritic-pearlitic microstructure. Dilatometry analysis was used to estimate
+the effect of heating rate on the phase transformation temperatures and to
+select an appropriate inter-critical temperature for final heat treatments. A
+thorough qualitative and quantitative microstructural characterization of the
+heat treated samples is performed using a wide range of characterization
+techniques. A complex multiphase, hierarchical microstructure consisting of
+ferritic matrix with embedded martensite and retained austenite is formed after
+all applied heat treatments. In turn, the ferritic matrix contains
+recrystallized and non-recrystallized grains. It is demonstrated that the
+ultrafast heating generally results in finer microstructure compared to the
+conventional heating independently on the soaking time. There is a significant
+effect of the soaking time on the volume fraction of martensite of the
+ultrafast heated material, while in the samples heated with conventional
+heating rate it remains relatively unchanged during soaking. Recrystallization,
+recovery and phase transformations occurring during soaking are discussed with
+respect to the applied heating rate.",1907.12767v1
+2019-10-24,Zero Field Cooled Exchange Bias Effect in Nano-Crystalline Mg-Ferrite Thin Film,"I report, Zero Field Cooled (ZFC) Exchange Bias (EB) effect in a single phase
+nanocrystalline Mg-ferrite thin film, deposited on an amorphous quartz
+substrate using pulsed laser ablation technique. The film showed a high ZFC EB
+shift (HE~ 190 Oe) at 5 K. The ZFC EB shift decreased with increasing
+temperature and disappeared at higher temperatures (T > 70 K). This Mg-ferrite
+thin film also showed Conventional Exchange Bias (CEB) effect, but unlike many
+CEB systems, the film showed decrease in the coercivity (HC) under the Field
+Cooled (FC) measurements. The film also showed training effect in ZFC
+measurements which followed the frozen spin relaxation behaviour. The observed
+exchange bias could be attributed to the pinning effect of the surface spins of
+frozen glassy states at the interface of large ferrimagnetic grains.",1910.10948v1
+2012-05-04,First-principles calculation of magnetoelastic coefficients and magnetostriction in the spinel ferrites CoFe2O4 and NiFe2O4,"We present calculations of magnetostriction constants for the spinel ferrites
+CoFe2O4 and NiFe2O4 using density functional theory within the GGA+U approach.
+Special emphasis is devoted to the influence of different possible cation
+distributions on the B site sublattice of the inverse spinel structure on the
+calculated elastic and magnetoelastic constants. We show that the resulting
+symmetry-lowering has only a negligible effect on the elastic constants of both
+systems as well as on the magnetoelastic response of NiFe2O4, whereas the
+magnetoelastic response of CoFe2O4 depends more strongly on the specific cation
+arrangement. In all cases our calculated magnetostriction constants are in good
+agreement with available experimental data. Our work thus paves the way for
+more detailed first-principles studies regarding the effect of stoichiometry
+and cation inversion on the magnetostrictive properties of spinel ferrites.",1205.0906v1
+2019-11-18,Chemical synthesis and magnetic properties of monodisperse cobalt ferrite nanoparticles,"In this work, a successful synthesis of magnetic cobalt ferrite (CoFe2O4)
+nanoparticles is presented. The synthesized CoFe2O4 nanoparticles have a
+spherical shape and highly monodisperse in the selected solvent. The effect of
+different reaction conditions such as temperature, reaction time and varying
+capping agents on the phase and morphology is studied. Scanning transmission
+electron microscopy showed that the size of these nanoparticles can be
+controlled by varying reaction conditions. Both X-ray diffraction and energy
+dispersive X-ray spectroscopy corroborate the formation of CoFe2O4 spinel
+structure with cubic symmetry. Due to optimized reaction parameters, each
+nanoparticle was shown to be a single magnetic domain with diameter ranges from
+6 to 16 nm. Finally, the magnetic investigations showed that the obtained
+nanoparticles are superparamagnetic with a small coercivity value of about 315
+Oe and a saturation magnetization of 58 emu/g at room temperature. These
+results make the cobalt ferrite nanoparticles promising for advanced magnetic
+nanodevices and biomagnetic applications.",1911.07496v1
+2020-09-08,On the assessment of an optimized method to determine the number of turns and the air gap length in ferrite-core low-frequency-current biased inductors,"This paper presents a first assessment of a design method aiming at the
+minimization of the number of turns $N$ and the air gap length $g$ in
+ferrite-core based low-frequency-current biased AC filter inductors. Several
+design cases are carried on a specific model of Power Module (PM) core, made of
+distinct ferrite materials and having different kinds of air gap arrangements
+The correspondingly obtained design results are firstly compared with the
+classic approach by linearization of the magnetic curve to calculate $N$ and
+the use of a fringing factor to determine $g$. Next, a refined design approach
+of specifying the inductance roll-off at the peak current and its potential
+limitations are discussed with respect to our design method. Finally, the
+behaviour of inductors operated beyond their design specifications is analyzed.",2009.03750v1
+2020-11-06,Phase boundary near a magnetic percolation transition,"Motivated by recent experimental observations [Phys. Rev. 96, 020407 (2017)]
+on hexagonal ferrites, we revisit the phase diagrams of diluted magnets close
+to the lattice percolation threshold. We perform large-scale Monte Carlo
+simulations of XY and Heisenberg models on both simple cubic lattices and
+lattices representing the crystal structure of the hexagonal ferrites. Close to
+the percolation threshold $p_c$, we find that the magnetic ordering temperature
+$T_c$ depends on the dilution $p$ via the power law $T_c \sim |p-p_c|^\phi$
+with exponent $\phi=1.09$, in agreement with classical percolation theory.
+However, this asymptotic critical region is very narrow, $|p-p_c| \lesssim
+0.04$. Outside of it, the shape of the phase boundary is well described, over a
+wide range of dilutions, by a nonuniversal power law with an exponent somewhat
+below unity. Nonetheless, the percolation scenario does not reproduce the
+experimentally observed relation $T_c \sim (x_c -x)^{2/3}$ in
+PbFe$_{12-x}$Ga$_x$O$_{19}$. We discuss the generality of our findings as well
+as implications for the physics of diluted hexagonal ferrites.",2011.03390v3
+2021-05-28,Anisotropic Magnon Spin Transport in Ultra-thin Spinel Ferrite Thin Films -- Evidence for Anisotropy in Exchange Stiffness,"We report measurements of magnon spin transport in a spinel ferrite,
+magnesium aluminum ferrite $\mathrm{MgAl_{0.5}Fe_{1.5}O_4}$ (MAFO), which has a
+substantial in-plane four-fold magnetic anisotropy. We observe spin diffusion
+lengths $> 0.8$ $\mathrm{\mu m}$ at room temperature in 6 nm films, with spin
+diffusion length 30% longer along the easy axes compared to the hard axes. The
+sign of this difference is opposite to the effects just of anisotropy in the
+magnetic energy for a uniform magnetic state. We suggest instead that
+accounting for anisotropy in exchange stiffness is necessary to explain these
+results.",2105.13943v1
+2021-08-09,Designing order-disorder transformation in high-entropy ferritic steels,"Order-disorder transformations hold an essential place in chemically complex
+high-entropy ferritic-steels (HEFSs) due to their critical technological
+application. The chemical inhomogeneity arising from mixing of multi-principal
+elements of varying chemistry can drive property altering changes at the atomic
+scale, in particular short-range order. Using density-functional theory based
+linear-response theory, we predict the effect of compositional tuning on the
+order-disorder transformation in ferritic steels -focusing on Cr-Ni-Al-Ti-Fe
+HEFSs. We show that Ti content in Cr-Ni-Al-Ti-Fe solid solutions can be tuned
+to modify short-range order that changes the order-disorder path from BCC-B2
+(Ti atomic-fraction = 0) to BCC-B2-L21 (Ti atomic-faction $>$ 0) consistent
+with existing experiments. Our study suggests that tuning degree of SRO through
+compositional variation can be used as an effective means to optimize phase
+selection in technologically useful alloys.",2108.04110v1
+2021-12-02,Strain Engineering of Magnetic Anisotropy in Epitaxial Films of Cobalt Ferrite,"Perpendicular magnetic anisotropy (PMA) energy up to
+$K_{\mathrm{u}}=6.1\pm0.8$ MJ m$^{-3}$ is demonstrated in this study by
+inducing large lattice-distortion exceeding 3% at room temperature in
+epitaxially distorted cobalt ferrite Co$ _{x} $Fe$ _{3-x} $O$ _{4} $ (x = 0.72)
+(001) thin films. Although the thin film materials include no rare-earth
+elements or noble metals, the observed $ K_{u} $ is larger than that of the
+neodymium-iron-boron compounds for high-performance permanent magnets. The
+large PMA is attributed to the significantly enhanced magneto-elastic effects,
+which are pronounced in distorted films with epitaxial lattice structures upon
+introducing a distortion control layer of composition Mg$ _{2-x} $Sn$_{1+x}$O$
+_{4} $. Surprisingly, the induced $ K_{u} $ can be quantitatively explained in
+terms of the agreement between the local crystal field of Co$ ^{2+} $ and the
+phenomenological magneto-elastic model, indicating that the linear response of
+induced $K_u$ is sufficiently valid even under lattice distortions as large as
+3.2%. Controlling tetragonal lattice deformation using a non-magnetic spinel
+layer for ferrites could be a promising protocol for developing materials with
+large magnetic anisotropies.",2112.00916v1
+2022-03-30,Origin of Perpendicular Magnetic Anisotropy in Co$_x$Fe$_{3-x}$O$_{4+δ}$ Thin Films Studied by X-ray Magnetic Circular and Linear Dichroisms,"We investigate the element-specific spin and orbital states and their roles
+on magnetic anisotropy in the Co-ferrite (Co$_x$Fe$_{3-x}$O$_{4+\delta}$ (001))
+thin films which exhibit perpendicular magnetic anisotropy (PMA). The origin of
+PMA in the low $x$ region ($x$ $<$ 1) can be mainly explained by the large
+perpendicular orbital magnetic moments in the Co$^{2+}$ (3$d^7$) states
+detected by X-ray magnetic circular and linear dichroisms (XMCD/XMLD). The XMLD
+for a PMA film ($x=0.2$) with square hysteresis curve shows the oblate charge
+distribution in the Co$^{2+}$ site, which is consistent with the change in
+local nearest neighbor distance in Co detected by extended X-ray absorption
+fine structure analysis. Our finding reveals that the microscopic origin of PMA
+in Co-ferrite comes from the enhanced orbital magnetic moments along
+out-of-plane [001] direction through in-plane charge distribution by tensile
+strain, which adds the material functionalities in spinel ferrite thin films
+from the viewpoint of strain and orbital magnetic moments.",2203.16061v1
+2023-02-13,Improper ferroelectricity in ultrathin hexagonal ferrites film,"The suppression of ferroelectricity in ultrathin films of improper
+ferroelectric hexagonal ferrites or manganites has been attributed to the
+effect of interfacial clamping, however, the quantitative understanding and
+related phenomenological model are still lacking. In this work, we report the
+paraelectric-to-ferroelectric phase transition of epitaxial h-ScFeO3 films with
+different thickness through in-situ reflection high-energy electron diffraction
+(RHEED). Based on the interfacial clamping model and the Landau theory, we show
+that the thickness-dependence of the ferroelectric Curie temperature can be
+understood in terms of the characteristic length of interfacial clamping layer
+and the bulk Curie temperature. Furthermore, we found that the critical
+thickness of improper ferroelectricity is proportional to the characteristic
+length of interfacial clamping layer. These results reveal the essential role
+of mechanical clamping from interface on the improper ferroelectricity of
+hexagonal ferrites or manganites, and could serve as the guidance to achieve
+robust improper ferroelectricity in ultrathin films.",2302.06532v1
+2023-03-14,Electromagnetic Waves Propagation along Tangentially Magnetised Bihyrotropic Layer (with Example of Spin Waves in Ferrite Plate),"Analytically, without magnetostatic approximation, the problem of
+electromagnetic wave propagation along arbitrary direction in a tangentially
+magnetized bihyrotropic layer has been solved. It is found that one can bring
+the Maxwell equations for this problem to the fourth order differential
+equation and the obtained biquadratic characteristic equation determines two
+different wave numbers kx21 and kx22 describing the wave distribution over the
+layer thickness. The dispersion equation describing wave propagation in the
+bihyrotropic layer was obtained for the case of real kx21 and kx22 values. It
+is shown that in a ferrite plate, which is a special case of a bihyrotropic
+layer, three types of wave distribution over the plate thickness can take
+place: surface-surface (when kx21 and kx22 are real numbers), volume-surface
+(kx21 is imaginary and kx22 is real) and volume-volume distribution (kx21 and
+kx22 are imaginary numbers). Characteristics of the surface spin wave in
+ferrite plate are investigated. It is found that dependences of the wave
+numbers kx21 and kx22 on the wave vector orientation are significantly
+different from the similar magnetostatic dependence for a large part of the
+wave spectrum.",2303.08800v1
+2023-09-27,On the potential of hard ferrite ceramics for permanent magnet technology -- a review on sintering strategies,"A plethora of modern technologies rely on permanent magnets for their
+operation, including many related to the transition towards a sustainable
+future, such as wind turbines or electric vehicles. Despite the overwhelming
+superiority of magnets based on rare-earth elements in terms of the magnetic
+performance, the harmful environmental impact of the mining of these raw
+materials, their uneven distribution on Earth and various political conflicts
+among countries leave no option but seeking for rare-earth-free alternatives.
+The family of the hexagonal ferrites or hexaferrites, and in particular the
+barium and strontium M-type ferrites (BaFe12O19 and SrFe12O19), are strong
+candidates for a partial rare-earth magnets substitution, and they are indeed
+successfully implemented in multiple applications. The manufacturing of
+hexaferrites into dense pieces (i.e. magnets) meeting the requirements of the
+specific application (e.g. magnetic and mechanical properties, shape) is not
+always straightforward, which has in many cases hampered the actual
+substitution at the industrial level. Here, past and on-going research on
+hexaferrites sintering is reviewed with a historical perspective, focusing on
+the challenges encountered and the solutions explored, and correlating the
+sintering approaches with the magnetic performance of the resulting ceramic
+magnet.",2309.15680v1
+2024-01-20,Charge transfer transitions and circular magnetooptics in ferrites,"The concept of charge-transfer (CT) transitions in ferrites is based on the
+cluster approach and takes into account the relevant interactions as the
+low-symmetry crystal field, spin-orbital, Zeeman, exchange and
+exchange-relativistic interactions. For all its simplicity, this concept yield
+a reliable qualitative and quantitative microscopic explanation of spectral,
+concentration, temperature, and field dependences of optic and magneto-optic
+properties ranging from the isotropic absorption as well as the optic
+anisotropy to the circular magneto-optics. In this review paper, starting with
+a critical analysis of the fundamental shortcomings of the ""first-principles""
+DFT-based band theory we present the main ideas and techniques of the cluster
+theory of the CT transitions to be main contributors to circular magneto-optics
+of ferrites.",2401.11267v1
+2013-03-01,Dispersive Casimir Pressure Effect from Surface Plasmon Quanta by Quasi 1D Metal Wires in Ferrite Disks and The Josephson Frequencies and Currents,"Ferrites are distinct material for electromagnetic applications due to its
+unique spin precession. In this paper, Casimir pressure effect by deploying
+magnetically tunable surface plasmon quanta in stratified structure of using
+ferrite and metal wires is presented. Previously, oscillating surface plasmon
+quanta were successfully included to modify first reflection and first
+transmission characteristics. The oscillating surface plasmon quanta in the
+modified reflection in such a system, not only does resolve in a typical matter
+in metamaterial, but also provide new applications such as creating Casimir
+pressure effects through the metamaterial composite shown in this paper. The
+Casimir pressure flips from attractive state to repulsive state is referred to
+cause mechanism of radiation from surface plasmon quanta. Both Casimir force
+analysis and the measured data of radiations indicate us the system develops
+quantized states by electric flux induced by ferromagnetic resonance. Quantum
+analysis is used to understand the discrete radiations spectra for our
+experimental measurement. The discrete radiations are reproduced by using time
+dependent Schr\""odinger representation. As a result, we find the Josephson
+frequency and Josephson current representations at room temperature and we used
+them for extrapolating voltage induced in excited ferrites. Josephson frequency
+at X-band is able to differentiate micron volt differences and it allows us to
+report the data for voltage induced by ferromagnetic resonance in ferrite at
+room temperature. It is understood that the radiation intensity depends on
+density of final states and excitation probability when we come to think the
+energy matter. It seems possible to create as high as 20mW microwave power
+inside waveguide at X-band.",1303.0205v2
+2023-09-24,Quantifying Li-content for compositional tailoring of lithium ferrite ceramics,"Owing to their multiple applications, lithium ferrites are relevant materials
+for several emerging technologies. For instance, LiFeO2 has been spotted as an
+alternative cathode material in Li-ion batteries, while LiFe5O8 is the lowest
+damping ferrite, holding promise in the field of spintronics. The Li-content in
+lithium ferrites has been shown to greatly affect the physical properties, and
+in turn, the performance of functional devices based on these materials.
+Despite this, lithium content is rarely accurately quantified, as a result of
+the low number of electrons in Li hindering its identification by means of
+routine materials characterization methods. In the present work, magnetic
+lithium ferrite powders with Li:Fe ratios of 1:1, 1:3 and 1:5 have been
+synthesized, successfully obtaining phase-pure materials (LiFeO2 and LiFe5O8),
+as well as a controlled mixture of both phases. The powders have been compacted
+and subsequently sintered by thermal treatment (Tmax = 1100 {\deg}C) to
+fabricate dense pellets which preserve the original Li:Fe ratios. Li-content on
+both powders and pellets has been determined by two independent methods: (i)
+Rutherford backscattering spectroscopy combined with nuclear reaction analysis
+and (ii) Rietveld analysis of powder X-ray diffraction data. With good
+agreement between both techniques, it has been confirmed that the Li:Fe ratios
+employed in the synthesis are maintained in the sintered ceramics. The same
+conclusion is drawn from spatially-resolved confocal Raman microscopy
+experiments on regions of a few microns. Field emission scanning electron
+microscopy has evidenced the substantial grain growth taking place during the
+sintering process - mean particle sizes rise from about 600 nm in the powders
+up to 3.8(6) um for dense LiFeO2 and 10(2) um for LiFe5O8 ceramics.",2309.14377v1
+2007-01-14,Nano Ferrites Microwave Complex Permeability and Permittivity Measurements by T/R Technique in Waveguide,"There is a huge demand to accurately determine the magneto-electrical
+properties of particles in the nano sized regime due to the modern IC
+technology revolution and biomedical application science. In this paper, we
+present a microwave waveguide measurement technique for complex permeability
+and permittivity of expensive nano sized magnetic powder materials. In the
+measurement process, Agilents 8510C vector network analyzer was used to have a
+standard TRL calibration for free space inside the waveguides. In order to
+maintain the recommended insertion phase range, a very thin prepared sample was
+loaded inside the calibrated waveguide. Also, the loaded materials magnetic and
+dielectric effects were considered into the cutoff wavelength of the
+propagation constant of the TE10 wave from the geometrical dimensions of the
+waveguides. This makes the measured permeability and permittivity more reliable
+than commonly used techniques. The six different compounds of nano sized
+ferrite powders (Fe3O4, CuFe2O4, CuFe2O4Zn, Fe2NiO3Zn, BaFe12O19, and
+SrFe12O19), in which the average diameter of nano particles is less than 40nm
+were purchased from Sigma-Aldrich, Inc for measurement purposes employing this
+technique. For industrial benefits, we present the complex permeability and
+permittivity on the frequency range from 3.95GHz to 5.85GHz. The measured
+results showed that the dielectric permittivity of these materials is quite
+different from those of solid state materials. Index Terms, Nano ferrites,
+waveguide technique, permeability, permittivity.",0701307v2
+2016-02-18,From Fe$_3$O$_4$/NiO bilayers to NiFe$_2$O$_4$-like thin films through Ni interdiffusion,"Ferrites with (inverse) spinel structure display a large variety of
+electronic and magnetic properties making some of them interesting for
+potential applications in spintronics. We investigate the thermally induced
+interdiffusion of Ni$^{2+}$ ions out of NiO into Fe$_3$O$_4$ ultrathin films
+resulting in off-stoichiometric nickelferrite-like thin layers. We synthesized
+epitaxial Fe$_3$O$_4$/NiO bilayers on Nb-doped SrTiO$_3$(001) substrates by
+means of reactive molecular beam epitaxy. Subsequently, we performed an
+annealing cycle comprising three steps at temperatures of 400\,$^{\circ}$C,
+600\,$^{\circ}$C, and 800\,$^{\circ}$C under an oxygen background atmosphere.
+We studied the changes of the chemical and electronic properties as result of
+each annealing step with help of hard x-ray photoelectron spectroscopy and
+found a rather homogenous distribution of Ni and Fe cations throughout the
+entire film after the overall annealing cycle. For one sample we observed a
+cationic distribution close to that of the spinel ferrite NiFe$_2$O$_4$.
+Further evidence comes from low energy electron diffraction patterns indicating
+a spinel type structure at the surface after annealing. Site and element
+specific hysteresis loops performed by x-ray magnetic circular dichroism
+uncovered the antiferrimagnetic alignment between the octahedral coordinated
+Ni$^{2+}$ and Fe$^{3+}$ ions and the Fe$^{3+}$ in tetrahedral coordination. We
+find a quite low coercive field of 0.02\,T, indicating a rather low defect
+concentration within the thin ferrite films.",1602.05773v1
+2017-03-19,"Magnetic properties of Sn-substituted Ni-Zn ferrite:synthesized from nano-sized powders of NiO, ZnO, Fe2O3 and SnO2","A series of Ni0.6-x/2Zn0.4-x/2SnxFe2O4 (x = 0.0, 0.05, 0.1, 0.15, 0.2 and
+0.3) (NZSFO) ferrite composites have been synthesized from nano powders using
+standard solid state reaction technique. The spinel cubic structure of the
+investigated samples has been observed by the X-ray diffraction (XRD). The
+magnetic properties such as saturation magnetization (Ms), remanent
+magnetization (Mr), coercive field (Hc) and Bohr magneton (B) are calculated
+from the hysteresis loops. The value of Ms is found to decrease with increasing
+Sn content in the samples. This change has been successfully explained by the
+variation of A-B interaction strength due to Sn substitution in different
+sites. The compositional stability and quality of the prepared ferrite
+composites have also been endorsed by the fairly constant initial permeability
+(/) over a wide range of frequency region. The decreasing trend of / with
+increasing Sn content has been observed. Curie temperature (TC) has found to
+increase with the increase in Sn content. Wide spread frequency utility zone
+indicates that the NZSFO can be considered as a good candidate for use in
+broadband pulse transformer and wide band read-write heads for video recording.
+The abnormal behavior for x = 0.05 has been explained with existing theory.",1703.06385v1
+2013-08-28,Innate character and theory model about channel segregation in a sand mold steel ingot,"The channel segregation is a severe casting defect in steel ingots. The
+formation of channel segregation is generally attributed to the solute
+partition and the interdendritic thermosolutal convection in the mushy zone. In
+this article, the channel segregation in a steel ingot was carefully
+characterized by detailed experimental observation. A different formation
+mechanism for the channel segregation was revealed. In the mushy zone of the
+ingot, large amount of separate MnS inclusions move laterally and upwards. Some
+MnS inclusions will remain in the moving trace of inclusions. Such residual MnS
+inclusions appear as large amount of separate MnS inclusion chains. In the
+subsequent solid phase transition process, promoted by the MnS chains, ferrite
+prefers to forms form the austenite near the MnS inclusions and shows as large
+amount of separate ferrite chains. Large amount of ferrite chains align in a
+strip-like zone, which results in so called channel segregation in
+macro-etching. The physical model about the driving force for the MnS movement
+is further theoretically analyzed. In the mushy zone, the interface tension
+resultant applied on the MnS inclusions can act as the drive force for the
+lateral movement of MnS inclusions. And the buoyance applied on the MnS
+inclusions act as the drive force for the upwards movement.",1308.6032v2
+2016-07-17,Second order perturbed Heisenberg Hamiltonian of Fe3O4 ultra-thin films,"Due to the wide range of applications, theoretical models of Fe3O4 films are
+found to be important. Ultra thin Fe3O4 films with ferrite structure have been
+theoretically investigated using second order perturbed modified Heisenberg
+Hamiltonian. Matrices for ultra thin films with two and three spin layers are
+presented in this manuscript. Total magnetic energy was expressed in terms of
+spin exchange interaction, magnetic dipole interaction, second order magnetic
+anisotropy and stress induced magnetic anisotropy. Magnetic properties were
+observed for films with two spin layers and variant second order magnetic
+anisotropy. For the film with three spin layers, second order anisotropy
+constant was fixed to avoid tedious derivations. Magnetic easy axis rotates
+toward the in plane direction as the number of spin layers is increased from
+two to three because the stress induced anisotropy energy dominates at higher
+number of spin layers. According to some other experimental data, the magnetic
+easy axis of thin films rotates toward the in plane direction as the thickness
+is increased. For ferrite film with two spin layers, magnetic easy and hard
+directions can be observed at 0.75 and 1.2 radians, respectively, when the
+ratio of stress induced anisotropy to the long range dipole interaction
+strength is 3.9. For ferrite film with three spin layers, magnetic easy and
+hard directions can be observed at 2.4 and 2.3 radians, respectively, when the
+ratio of stress induced anisotropy to the long range dipole interaction
+strength is 4.2.",1611.02225v2
+2017-09-28,Magnetization and Anisotropy of Cobalt Ferrite Thin Films,"The magnetization of thin films of cobalt ferrite frequently falls far below
+the bulk value of 455 kAm-1, which corresponds to an inverse cation
+distribution in the spinel structure with a significant orbital moment of about
+0.6 muB that is associated with the octahedrally-coordinated Co2+ ions. The
+orbital moment is responsible for the magnetostriction and magnetocrystalline
+anisotropy, and its sensitivity to imposed strain. We have systematically
+investigated the structure and magnetism of films produced by pulsed-laser
+deposition on different substrates (TiO2, MgO, MgAl2O4, SrTiO3, LSAT, LaAlO3)
+and as a function of temperature (500-700 C) and oxygen pressure (10-4 - 10
+Pa). Magnetization at room-temperature ranges from 60 to 440 kAm-1, and
+uniaxial substrate-induced anisotropy ranges from +220 kJm-3 for films on
+deposited on MgO (100) to -2100 kJm-3 for films deposited on MgAl2O4 (100),
+where the room-temperature anisotropy field reaches 14 T. No rearrangement of
+high-spin Fe3+ and Co2+ cations on tetrahedral and octahedral sites can reduce
+the magnetization below the bulk value, but a switch from Fe3+ and Co2+ to Fe2+
+and low-spin Co3+ on octahedral sites will reduce the low-temperature
+magnetization to 120 kAm-1, and a consequent reduction of Curie temperature can
+bring the room-temperature value to near zero. Possible reasons for the
+appearance of low-spin cobalt in the thin films are discussed.
+  Keywords; Cobalt ferrite, thin films, pulsed-laser deposition, low-spin Co3+,
+strain engineering of magnetization.",1709.09965v1
+2017-11-14,Cluster dynamics modeling of Mn-Ni-Si precipitates in ferritic-martensitic steel under irradiation,"Mn-Ni-Si precipitates (MNSPs) are known to be responsible for
+irradiation-induced hardening and embrittlement in structural alloys used in
+nuclear reactors. Studies have shown that precipitation of the MNSPs in 9-Cr
+ferritic-martensitic (F-M) alloys, such as T91, is strongly associated with
+heterogeneous nucleation on dislocations, coupled with radiation-induced solute
+segregation to these sinks. Therefore it is important to develop advanced
+predictive models for Mn-Ni-Si precipitation in F-M alloys under irradiation
+based on an understanding of the underlying mechanisms. Here we use a cluster
+dynamics model, which includes multiple effects of dislocations, to study the
+evolution of MNSPs in a commercial F-M alloy T91. The model predictions are
+calibrated by data from proton irradiation experiments at 400 {\deg}C.
+Radiation induced solute segregation at dislocations is evaluated by a
+continuum model that is integrated into the cluster dynamics simulations,
+including the effects of dislocations as heterogeneous nucleation sites. The
+result shows that MNSPs in T91 are primarily irradiation-induced and, in
+particular, both heterogeneous nucleation and radiation-induced segregation at
+dislocations are necessary to rationalize the experimental observations.",1711.05008v1
+2018-06-29,High quality cobalt ferrite ultrathin films with large inversion parameter grown in epitaxy on Ag(001),"Cobalt ferrite ultrathin films with inverse spinel structure are among the
+best candidates for spin-filtering at room temperature. We have fabricated
+high-quality epitaxial ultrathin CoFe2O4 layers on Ag(001) following a
+three-step method: an ultrathin metallic CoFe2 alloy was first grown in
+coherent epitaxy on the substrate, and then treated twice with O2, first at RT
+and then during annealing. The epitaxial orientation, the surface, interface
+and film structure were resolved combining LEED, STM, Auger and in situ GIXRD.
+A slight tetragonal distortion was observed, that should drive the easy
+magnetization axis in plane due to the large magneto-elastic coupling of such a
+material. The so-called inversion parameter, i.e. the Co fraction occupying
+octahedral sites in the ferrite spinel structure, is a key element for its
+spin-dependent electronic gap. It was obtained through in-situ x-ray resonant
+diffraction measurements collected at both the Co and Fe K edges. The data
+analysis was performed using the FDMNES code and showed that Co ions are
+predominantly located at octahedral sites with an inversion parameter of 0.88
++- 0.05. Ex-situ XPS gave an estimation in accordance with the values obtained
+through diffraction analysis.",1807.00060v1
+2019-03-04,Structural and magnetic properties in sputtered iron oxide epitaxial thin films -- Magnetite Fe$_3$O$_4$ and epsilon ferrite e-Fe$_2$O$_3$,"Epitaxial thin film fabrication of iron oxides including magnetite Fe3O4 and
+epsilon-ferrite epsilon-Fe2O3 with the potential for advancing electromagnetic
+devices has been investigated, which led to the first ever epsilon-ferrite
+epitaxial layer being synthesized in the conventional sputtering process.
+Concerning Fe3O4 (100) / MgO (100) films, a cube-on-cube epitaxial relationship
+and sharp rocking curves with FWHM of 50 - 350 arcsec were confirmed regardless
+of the small amount of Ge additions. Sputtering Ar gas pressure PAr heavily
+influenced their magnetic and transport properties. High PAr = 15 mTorr caused
+a high magnetization of 6.52 kG for the Ge added sample and the clear Verwey
+transition at 122 K for the non Ge addition case. Conversion electron Mossbauer
+spectroscopy (CEMS) measurements revealed that low PAr < 10 mTorr causes Fe/O
+off-stoichiometry on the oxidizing side for the non Ge addition case and the
+reductive side for the Ge addition case, respectively. Regarding the
+epsilon-Fe2O3 (001) / SrTiO3(111) epilayer synthesis, bilayer microstructure
+composed of an approximately 5nm thick initially grown epsilon-Fe2O3 (001)
+epilayer and subsequently grown e-Fe2O3 (001) epilayer was confirmed from
+cross-sectional TEM observations. The coexistence of magnetically hard and soft
+phases was confirmed from the magnetization measurements. As a possible
+application of the single nm thick epsilon-Fe2O3 layer, 4-resistive-state
+multiferroic tunnel junction (MFTJ) is considered.",1903.01022v1
+2020-09-10,Charge-Spin Interconversion in Epitaxial Pt Probed by Spin-Orbit Torques in a Magnetic Insulator,"We measure spin-orbit torques (SOTs) in a unique model system of
+all-epitaxial ferrite/Pt bilayers to gain insights into charge-spin
+interconversion in Pt. With negligible electronic conduction in the insulating
+ferrite, the crystalline Pt film acts as the sole source of charge-to-spin
+conversion. A small field-like SOT independent of Pt thickness suggests a weak
+Rashba-Edelstein effect at the ferrite/Pt interface. By contrast, we observe a
+sizable damping-like SOT that depends on the Pt thickness, from which we deduce
+the dominance of an extrinsic spin-Hall effect (skew scattering) and
+Dyakonov-Perel spin relaxation in the crystalline Pt film. Furthermore, our
+results point to a large internal spin-Hall ratio of $\approx$0.8 in epitaxial
+Pt. Our experimental work takes an essential step towards understanding the
+mechanisms of charge-spin interconversion and SOTs in Pt-based
+heterostructures, which are crucial for power-efficient spintronic devices.",2009.04894v3
+2020-10-22,"Structural and Magnetic Characterization of CuxMn1-xFe2O4 (x= 0.0, 0.25) Ferrites Using Neutron Diffraction and Other Techniques","Manganese ferrite (MnFe2O4) and copper doped manganese ferrite
+(Mn0.75Cu0.25Fe2O4) soft materials were synthesized through solid-state
+sintering method. The phase purity and quality were confirmed from x-ray
+diffraction patterns. Then the samples were subjected to neutron diffraction
+experiment and the diffraction data were analyzed using FullProf software
+package. The surface morphology of the soft material samples was studied using
+a scanning electron microscope (SEM). Crystal parameters, crystallite
+parameters, occupancy at A and B sites of the spinel structure, magnetic
+moments of the atoms at various locations, symmetries, oxygen position
+parameters, bond lengths etc. were measured and compared with the reference
+data. In MnFe2O4, both octahedral (A) and tetrahedral (B) positions are shared
+by Mn2+ and Fe2+/3+ cations, here A site is predominantly occupied by Fe2+ and
+B site is occupied by Mn at 0.825 occupancy. The Cu2+ ions in Cu0.25Mn0.75Fe2O4
+mostly occupy the B site. Copper mostly occupy the Octahedral (16d) sites. The
+length of the cubic lattice decreases with the increasing Copper content. The
+magnetic properties, i.e. A or B site magnetic moments, net magnetic moment
+etc. were measured using neutron diffraction analysis and compared with the
+bulk magnetic properties measured with VSM studies.",2010.11739v1
+2021-10-18,Control of Electrochemical Corrosion Properties by Influencing Mn Partitioning through Intercritically Annealing of Medium-Mn Steel,"Medium-Mn steels exhibit excellent mechanical properties and lower production
+costs compared to high-Mn steels, which makes them a potential material for
+future application in the automotive industry. Intercritical annealing (ICA)
+after cold rolling allows to control the stacking fault energy (SFE) of
+austenite, the fraction of ferrite and reverted austenite, and the element
+partitioning (especially Mn). Although Mn deteriorates the corrosion behavior
+of Fe-Mn-Al alloys, the influence of austenite fraction and element
+partitioning of Mn on the electrochemical corrosion behavior has not been
+investigated yet. Therefore, the electrochemical corrosion behavior in 0.1 M
+H2SO4 of X6MnAl12-3, which was intercritically annealed for 2 h at 550 {\deg}C,
+600 {\deg}C and 700 {\deg}C, was investigated by potentiodynamic polarization
+(PDP), electrochemical impedance spectroscopy (EIS) and mass spectroscopy with
+inductively coupled plasma (ICP-MS). Additionally, specimens after 1 h and 24 h
+of immersion were examined via SEM to visualize the corrosion damage. The ICA
+specimens showed a selective dissolution of reverted austenite due to its
+micro-galvanic coupling with the adjacent ferrite. The severity of the
+micro-galvanic coupling can be reduced by decreasing the interface area as well
+as the chemical gradient of mainly Mn between ferrite and reverted austenite by
+ICA.",2110.09205v1
+2022-06-30,Modified Z-Phase Formation in a 12% Cr Tempered Martensite Ferritic Steel during Long-Term Creep,"The formation of modified Z-phase in a 12Cr1MoV (German grade: X20) tempered
+martensite ferritic (TMF) steel subjected to interrupted long-term
+creep-testing at 550$^{\circ}$C and 120 MPa was investigated. Quantitative
+volumetric measurements collected from thin-foil and extraction replica samples
+showed that modified Z-phase precipitated in both the uniformly-elongated gauge
+($f_v$: 0.23 $\pm$ 0.02 %) and thread regions ($f_v$: 0.06 $\pm$ 0.01 %) of the
+sample that ruptured after 139 kh. The formation of modified Z-phase was
+accompanied by a progressive dissolution of MX precipitates, which decreased
+from ($f_v$: 0.16 $\pm$ 0.02 %) for the initial state to ($f_v$: 0.03 $\pm$
+0.01 %) in the uniformly-elongated gauge section of the sample tested to
+failure. The interparticle spacing of the creep-strengthening MX particles
+increased from ($\lambda_{3D}$: 0.55 $\pm$ 0.05 $\mu m$) in the initial state
+to ($\lambda_{3D}$: 1.01 $\pm$ 0.10 $\mu m$) for the uniformly-elongated gauge
+section of the ruptured sample, while the thread region had an interparticle
+spacing of ($\lambda_{3D}$: 0.60 $\pm$ 0.05 $\mu m$). The locally deformed
+fracture region had an increased phase fraction of modified Z-phase ($f_v$:
+0.40 $\pm$ 0.20 %), which implies that localised creep-strain strongly promotes
+the formation of modified Z-phase. The modified Z-phase precipitates did not
+form only on prior-austenite grain boundaries and formed throughout the
+tempered martensite ferritic grain structure.",2206.15070v1
+2022-08-24,Complex magnetoelectric effect in PFN-PT/CoFe$_{2-x}$Zn$_x$O$_4$ bulk particulate composites,"The structural, dielectric, magnetic, and magnetoelectric (ME) properties of
+particulate composites containing lead-iron niobate and lead titanate
+piezoelectric 0.94[PbFe$_{0.5}$Nb$_{0.5}$O$_3$]-0.06[PbTi$_{0.5}$O$_3$]
+(PFN-PT) and Zn-substituted cobalt ferrite magnetostrictive
+CoFe$_{2-x}$Zn$_{x}$O$_4$ (CF$_{2-x}$Z$_{x}$O);
+0.6(PFN-PT)/0.4(CF$_{2-x}$Z$_{x}$O), x=0, 0.025, 0.1, 0.2, 0.3 (with ratio of
+60 Wt\% ferroelectric and 40 Wt\% ferrite); have been investigated. We
+investigated the ME voltage coefficient as a complex quantity for all composite
+samples using the dynamic piezomagnetic coefficient, $q^{ac}$=$\partial
+\lambda^{ac}/{\partial H}$. The results reveal that tuning the magnetostrictive
+phase has a strong effect on the real part of the ME voltage coefficient.
+Doping zinc into cobalt ferrite modified the magnetic properties of the
+magnetic phase, such as magnetic anisotropy and coercive field, and hence the
+ME properties. The highest ME coefficient value of 12.33 $\frac{mV}{cm. Oe}$
+was obtained for x=0.1 at the magnetic field of 755 Oe. In addition, the
+magnetic field at which the maximum value of the ME coefficient was observed
+($H_{peak}$) strongly depends on the value of Zn substitution. The results were
+interpreted using the magnetic field dependence of the CF$_{2-x}$Z$_{x}$O
+magnetostriction.",2208.11317v1
+2023-05-07,Band gap and pseudocapacitance of Gd$_2$O$_3$ doped with Ni$_{0.5}$Zn$_{0.5}$Fe$_2$O$_4$,"Herein, we present a detailed study of the structural, optical, and
+electrochemical responses of Gd$_2$O$_3$ doped with nickel zinc ferrite
+nanoparticles. Doping of Ni$_{0.5}$Zn$_{0.5}$Fe$_2$O$_4$ nanoparticles to
+Gd$_2$O$_3$ powder was done through thermal decomposition at 1000 C. The
+average grain size of the mixture was determined to be approximately 95 nm, and
+phases of cubic Gd$_2$O$_3$, GdO, and orthorhombic prisms of GdFeO$_3$ were
+identified. The focused ion beam energy dispersive X-ray spectrum (FIB-EDX)
+mapping results clearly show the morphology of the particles with Gd and Fe as
+the dominant elements. The structural data were compared with the spectroscopic
+measurements confirming the formation of multiple phases of oxides and
+ferrites. The measured optical band gap is significantly redshifted to 1.8 eV
+and is close to that of nitride compounds of gadolinium metal. The measured
+specific capacitance was almost 7 Fg-1 at a current density of 1 Ag-1, showing
+a small drop of 27% when the current density is increased to 10 Ag-1. Cyclic
+voltammetry (CV) plots of the ferrite doped Gd2O3 electrode at a scan rate of 5
+to 100 mV/s indicate the pseudocapacitive nature of the material.",2305.04370v1
+2023-06-06,Stress evolution in plastically deformed austenitic and ferritic steels determined using angle- and energy-dispersive diffraction,"In the presented research, the intergranular elastic interaction and the
+second-order plastic incompatibility stress in textured ferritic and austenitic
+steels were investigated by means of diffraction. The lattice strains were
+measured inside the samples by the multiple reflection method using high energy
+X-rays diffraction during uniaxial in situ tensile tests. Comparing experiment
+with various models of intergranular interaction, it was found that the
+Eshelby-Kr\""oner model correctly approximates the X-ray stress factors (XSFs)
+for different reflections hkl and scattering vector orientations. The verified
+XSFs were used to investigate the evolution of the first and second-order
+stresses in both austenitic and ferritic steels. It was shown that considering
+only the elastic anisotropy, the non-linearity of $\sin^2{\psi}$ plots cannot
+be explained by crystallographic texture. Therefore, a more advanced method
+based on elastic-plastic self-consistent modeling (EPSC) is required for the
+analysis. Using such methodology the non-linearities of $\cos^2{\phi}$ plots
+were explained, and the evolutions of the first and second-order stresses were
+determined. It was found that plastic deformation of about 1- 2% can completely
+exchange the state of second-order plastic incompatibility stresses.",2306.03804v1
+2023-06-26,Microscopic conductivity of passive films on ferritic stainless steel for hydrogen fuel cells,"Hydrogen fuel cells offer a clean and sustainable energy conversion solution.
+The bipolar separator plate, a critical component in fuel cells, plays a vital
+role in preventing reactant gas cross-contamination and facilitating efficient
+ion transport in a fuel cell. High chromium ferritic stainless steel with an
+artificially formed thin chromium oxide passive film has recently gained
+attention due to its superior electrical conductivity and corrosion resistance,
+making it a suitable material for separators. In this study, we investigate the
+microscopic electrical conductivity of the intrinsic passive oxide film on such
+ferritic stainless steel. Through advanced surface characterization techniques
+such as current sensing atomic force microscopy and scanning tunneling
+microscopy/spectroscopy, we discover highly conductive regions within the film
+that vary depending on location. These findings provide valuable insights into
+the behavior of the passive oxide film in fuel cells. By understanding the
+microscopic electrical properties, we can enhance the design and performance of
+separator materials in hydrogen fuel cells. Ultimately, this research
+contributes to a broader understanding of separator materials and supports the
+wider application of hydrogen fuel cells.",2306.14513v1
+2024-01-08,Theory of x-ray absorption spectroscopy for ferrites,"The theoretical calculation of the interaction of electromagnetic radiation
+with matter remains a challenging problem for contemporary $ab$ $initio$
+electronic structure methods, in particular for x-ray spectroscopies. This is
+not only due to the strong interaction between the core-hole and the
+photo-excited electron, but also due to the elusive multiplet effects that
+arise from the Coulomb interaction among the valence electrons. In this work we
+report a method based on density-functional theory in conjunction with
+multiplet ligand-field theory to investigate various core-level spectroscopies,
+in particular x-ray absorption spectroscopy (XAS) and x-ray magnetic circular
+dichroism (XMCD). The developed computational scheme is applied to the
+$L_{2,3}$ XAS edges of magnetite (Fe$_3$O$_4$) as well as cobalt ferrite
+(CoFe$_2$O$_4$) and nickel ferrite (NiFe$_2$O$_4$) and the corresponding XMCD
+spectra. The results are in overall good agreement with experimental
+observations, both regarding the XAS $L_2$/$L_3$ branching ratio, the peak
+positions as well as the relative intensities. The agreement between theory and
+experiment is equally good for XAS and the XMCD spectra, for all studied
+systems. The results are analyzed in terms of $e_g$ and $t_{2g}$ orbitals
+contributions and the importance of optimizing the Slater parameters. The
+analysis also highlights the strong effect of the $2p$-$3d$ interaction in
+x-ray spectroscopy.",2401.03858v1
+2024-01-21,"HARDCORE: H-field and power loss estimation for arbitrary waveforms with residual, dilated convolutional neural networks in ferrite cores","The MagNet Challenge 2023 calls upon competitors to develop data-driven
+models for the material-specific, waveform-agnostic estimation of steady-state
+power losses in toroidal ferrite cores. The following HARDCORE (H-field and
+power loss estimation for Arbitrary waveforms with Residual, Dilated
+convolutional neural networks in ferrite COREs) approach shows that a residual
+convolutional neural network with physics-informed extensions can serve this
+task efficiently when trained on observational data beforehand. One key
+solution element is an intermediate model layer which first reconstructs the bh
+curve and then estimates the power losses based on the curve's area rendering
+the proposed topology physically interpretable. In addition, emphasis was
+placed on expert-based feature engineering and information-rich inputs in order
+to enable a lean model architecture. A model is trained from scratch for each
+material, while the topology remains the same. A Pareto-style trade-off between
+model size and estimation accuracy is demonstrated, which yields an optimum at
+as low as 1755 parameters and down to below 8\,\% for the 95-th percentile of
+the relative error for the worst-case material with sufficient samples.",2401.11488v2
+2024-02-23,Effect of temperature and copper doping on the heterogeneous Fenton-like activity of Cu$_x$Fe$_{3-x}$O$_4$ nanoparticles,"Ferrite nanoparticles serve as potent heterogeneous Fenton-like catalysts,
+producing reactive oxygen species (ROS) for decomposing organic pollutants. We
+investigated the impact of temperature and copper content on the catalytic
+activity of nanoparticles with different oxidation states of iron. Via
+solvothermal synthesis, we fabricated copper-doped magnetite
+(Cu$_x$Fe$_{3-x}$O$_4$) with a Fe$^{2+}$/Fe ratio ~0.33 for the undoped system.
+Using a microwave-assisted method, we produced copper-doped oxidized ferrites,
+yielding a Fe$^{2+}$/Fe ratio of ~0.11 for the undoped nanoparticles. The ROS
+generated by the catalyst were identified and quantified by electron
+paramagnetic resonance, while optical spectroscopy allowed us to evaluate its
+effectiveness for the degradation of a model organic dye. At room temperature,
+the magnetite nanoparticles exhibited the most $\cdot$OH radical production and
+achieved almost 90% dye discoloration in 2 hours. This efficiency decreased
+with increasing Cu concentration, concurrently with a decrease in $\cdot$OH
+generation. Conversely, above room temperature, Cu-doped nanoparticles
+significantly enhance the dye degradation, reaching 100% discoloration at
+90$^\circ$C. This enhancement is accompanied by a systematic increase in the
+kinetic constants, obtained from reaction equations, with Cu doping. This study
+highlights the superior stability and high-temperature catalytic advantages of
+copper ferrite holding promise for enhancing the performance of nanocatalysts
+for decomposing organic contaminants.",2402.15338v1
+2008-11-22,Flexomagnetoelectric effect in bismuth ferrite,"There is a profound analogy between inhomogeneous magnetoelectric effect in
+multiferroics and flexoelectric effect in liquid crystals. This similarity
+gives rise to the flexomagnetoelectric polarization induced by spin modulation.
+The theoretical estimations of flexomagnetoelectric polarization agree with the
+value of jumps of polarization in magnetoelectric dependences (~20muC/m^2)
+observed at spin cycloid suppression at critical magnetic field 200kOe.",0811.3677v1
+2014-01-08,Mechanical behavior of steels: from fundamental mechanisms to macroscopic deformation,"My scientific activities aim at understand and predict the mechanical
+behaviour of steels, from fundamental mechanisms to macroscopic deformation.
+This manuscript is dedicated to the TWIP effect (TWinning Induced Plasticity)
+of high manganese austenitic steels and DP effect (Dual-Phase) in more
+conventional Ferrite-Martensite steels.",1401.2099v1
+2017-01-31,Heterodiffusion coefficients in α-iron,"The diffusion of tungsten in {\alpha}-iron is important for the application
+of ferritic-iron alloys to thermal power plants. These data, over a wide
+temperature range across the Curie temperature, have been recently reported. We
+show that these diffusion coefficients can be satisfactory reproduced in terms
+of the bulk elastic and expansivity data by means of a thermodynamical model
+that interconnects point defects parameters with bulk qualities.",1701.08993v1
+2020-12-28,"Structural, optical and magnetic properties of nanostructured Cr-substituted Ni-Zn spinel ferrites synthesized by a microwave combustion method","Nanoparticles of Cr3+-substituted Ni-Zn ferrites with a general formula
+Ni0.4Zn0.6-xCrxFe2O4 (x = 0.0 - 0.6) have been synthesized via a facile
+microwave combustion route. The crystalline phase has been characterized by
+XRD, TEM, FT-I and XPS revealing the spinel ferrite structure without extra
+phases. Crystallite sizes of 23 - 32 nm as estimated by XRD analyses, after
+corrections for crystal stains by Williamson-Hall method, are comparable to the
+average particle sizes observed by TEM which indicates successfully synthesized
+nanocrystals. Rietveld refinement analyses of the XRD patterns have inferred a
+monotonic decrease behavior of the lattice parameter with Cr doping in
+agreement with Vegard's law of solid solution series. Furthermore, cations
+distribution with an increased inversion factor indicate the B-site preference
+of Cr3+ ions. The oxidation states and cations distribution indicated by XPS
+results imply the Cr3+ doping on the account of Zn2+ ions and a partial
+reduction of Fe3+ to Fe2+ to keep the charge balance in a composition series of
+(Ni2+)0.4(Zn2+, Cr3+)0.6(Fe2+, Fe3+)2(O2-)4. The optical properties were
+explored by optical UV-Vis spectroscopy indicating allowed direct transitions
+with band gap energy that decreases from 3.9 eV to 3.7 eV with Cr doping.
+Furthermore, the photocatalytic activity for the degradation of methyl orange
+(MO) dye was investigated showing largely enhanced photodecomposition up to 30%
+of MO dye over Ni0.4Cr0.6Fe2O4 for 6 hours. A vibrating sample magnetometry
+(VSM) measurements at room temperature show further enhancement in the
+saturation magnetization of Ni0.4Zn0.6Fe2O4 , the highest in Ni-Zn ferrites,
+from about 60 to 70 emu/g with the increase of Cr concentration up to x = 0.1,
+while the coercivity shows a general increase in the whole range of Cr doping.",2012.14232v1
+2022-03-22,"Effect of ECAP and heat treatment on mechanical properties, stress relaxation behavior and corrosion resistance of a 321-type austenitic steel with increased delta-ferrite content","Hot rolled commercial metastable austenitic steel 0.8C-18Cr-10Ni-0.1Ti
+(Russian industrial name 08X18H10T, analog 321L) with strongly elongated thin
+delta-ferrite particles in its microstructure was the object of investigations.
+The lengths of these delta-particles were up to 500 mkm, the thickness was 10
+mkm. The formation of the strain-induced martensite as well as the grinding of
+the austenite and of the delta-ferrite grains take place during ECAP. During
+the annealing of the UFG steel, the formation of the delta-phase particles
+takes place. These particles affect the grain boundary migration and the
+strength of the steel. However, a reduction of the Hall-Petch coefficient as
+compared to the coarse-grained (CG) steel due to the fragmentation of the
+delta-ferrite particles was observed. The samples of the UFG steel were found
+to have 2-3 times higher stress relaxation resistance as compared to the CG
+steel (a higher macroelasticity stress and a lower stress relaxation
+magnitude). The differences in the stress relaxation resistance of the UFG and
+CG steels were investigated. ECAP was shown to result in an increase in the
+corrosion rate and in an increased tendency to the intergranular corrosion
+(IGC). The reduction of the corrosion resistance of the UFG steel was found to
+originate from the increase in the fraction of the strain-induced martensite
+during ECAP.",2203.12102v1
+2001-04-27,Faraday rotation spectra of bismuth-substituted ferrite garnet films with in-plane magnetization,"Single crystalline films of bismuth-substituted ferrite garnets have been
+synthesized by the liquid phase epitaxy method where GGG substrates are dipped
+into the flux. The growth parameters are controlled to obtain films with
+in-plane magnetization and virtually no domain activity, which makes them
+excellently suited for magnetooptic imaging. The Faraday rotation spectra were
+measured across the visible range of wavelengths. To interprete the spectra we
+present a simple model based on the existence of two optical transitions of
+diamagnetic character, one tetrahedral and one octahedral. We find excellent
+agreement between the model and our experimental results for photon energies
+between 1.77 and 2.53 eV, corresponding to wavelengths between 700 and 490 nm.
+It is shown that the Faraday rotation changes significantly with the amount of
+substituted gallium and bismuth. Furthermore, the experimental results suggest
+that the magnetooptic response changes linearly with the bismuth substitution.",0104536v3
+2003-07-10,Theory of low frequency magnetoelectric coupling in magnetostrictive-piezoelectric bilayers,"A theoretical model is presented for low-frequency magnetoelectric (ME)
+effects in bilayers of magnetostrictive and piezoelectric phases. A novel
+approach, the introduction of an interface coupling parameter k, is proposed
+for the consideration of actual boundary conditions at the interface. An
+averaging method is used to estimate effective material parameters. Expressions
+for ME voltage coefficients are obtained by solving elastostatic and
+electrostatic equations. We consider both unclamped and rigidly clamped
+bilayers and three different field orientations of importance: (i) longitudinal
+fields in which the poling field, bias field and ac fields are all parallel to
+each other and perpendicular to the sample plane; (ii) transverse fields for
+magnetic fields parallel to each other and perpendicular to electric fields,
+and (iii) in-plane longitudinal fields for all the fields parallel to each
+other and to the sample plane. The theory predicts a giant ME coupling for
+bilayers with cobalt ferrite (CFO), nickel ferrite (NFO), or lanthanum
+strontium manganite (LSMO) for the magnetostrictive phase and barium titanate
+(BTO) or lead zirconate titanate (PZT) for the piezoelectric phase.",0307264v1
+2004-07-01,Universal transport properties of open microwave cavities with and without time-reversal symmetry,"We measure the transmission through asymmetric and reflection-symmetric
+chaotic microwave cavities in dependence of the number of attached wave guides.
+Ferrite cylinders are placed inside the cavities to break time-reversal
+symmetry. The phase-breaking properties of the ferrite and its range of
+applicability are discussed in detail. Random matrix theory predictions for the
+distribution of transmission coefficients T and their energy derivative dT/dE
+are extended to account for absorption. Using the absorption strength as a
+fitting parameter, we find good agreement between universal transmission
+fluctuations predicted by theory and the experimental data.",0407046v1
+2005-02-15,Influence of strain and oxygen vacancies on the magnetoelectric properties of multiferroic bismuth ferrite,"The dependencies on strain and oxygen vacancies of the ferroelectric
+polarization and the weak ferromagnetic magnetization in the multiferroic
+material bismuth ferrite, BiFeO_3, are investigated using first principles
+density functional theory calculations. The electric polarization is found to
+be rather independent of strain, in striking contrast to most conventional
+perovskite ferroelectrics. It is also not significantly affected by oxygen
+vacancies, or by the combined presence of strain and oxygen vacancies. The
+magnetization is also unaffected by strain, however the incorporation of oxygen
+vacancies can alter the magnetization slightly, and also leads to the formation
+of Fe^{2+}. These results are discussed in light of recent experiments on
+epitaxial films of BiFeO_3 which reported a strong thickness dependence of both
+magnetization and polarization.",0502364v1
+2006-06-01,Microstructural characterization and kinetics modelling of vermicular cast irons,"Several experimental techniques are used for phase identification and
+microstructure characterization of austempered vermicular cast irons (XRD, SEM,
+TEM and Mossbauer spectroscopy). Acicular structures were found to be composed
+by ferrite and austenite with average sizes compatible with those reported for
+bainitic ferrite in steels and Austempered Ductile Iron. An assessment of the
+free energy change involved in the austenite to bainite transformation assuming
+a plate-like nucleation shape for bainite gave an average characteristic length
+close to the observed from statistical length distributions. The kinetics of
+the transformation was modelled in the Avrami framework; both the diffusion
+controlled and the diffusionless growth hypothesis were considered in order to
+elucidate the mechanism underlying the austempering phase transformation.
+Results indicated that diffusion of C is the responsible of the nucleation
+process of the bainite sheaves, that appear as a consequence of a localized
+displacive transformation when the C concentration is adequate, but further
+growth of the bainite plates is almost suppressed.",0606031v2
+2006-08-07,Electronic structure of normal and inverse spinel ferrites from first principles,"We apply the self-interaction corrected local spin density %(SIC-LSD)
+approximation to study the electronic structure and magnetic properties of the
+spinel ferrites MnFe$_{2}$O$_{4}$, Fe$_{3}$O$_{4}$, CoFe$_{2}$O$_{4}$, and
+NiFe$_{2}$O$_{4}$. We concentrate on establishing the nominal valence of the
+transition metal elements and the ground state structure, based on the study of
+various valence scenarios for both the inverse and normal spinel structures for
+all the systems. For both structures we find all the studied compounds to be
+insulating, but with smaller gaps in the normal spinel scenario. On the
+contrary, the calculated spin magnetic moments and the exchange splitting of
+the conduction bands are seen to increase dramatically when moving from the
+inverse spinel structure to the normal spinel kind. We find substantial orbital
+moments for NiFe$_{2}$O$_{4}$ and CoFe$_{2}$O$_{4}$.",0608168v1
+2007-05-20,The beta Phase of Multiferroic Bismuth Ferrite and its beta-gamma Metal-Insulator Transition,"We show that epitaxial (001) thin films of multiferroic bismuth ferrite
+BiFeO3 are monoclinic at room temperature instead of tetragonal or Rhombohedral
+as reported earlier . We report a orthorhombic order-disorder beta-phase
+between 820C and 950C contrary to the earlier report. The transition sequence
+monoclinic-orthorhombic phase in (001)BiFeO3 thin film
+(rhombohedral-orthorhombic transition in single crystal) resembles that of
+BaTiO3 or PbSc1/2Ta1/2O3. The transition to the cubic $\gamma$-phase causes an
+abrupt collapse of the bandgap toward zero (insulator-metal transition) at the
+orthorhombic-cubic beta-gamma transition around 950C. This transition is
+similar to the metal-insulator transition in Ba0.6K0.4BiO3.",0705.2883v3
+2007-05-27,Influence of pulsed magnetic field on single- and two-pulse nuclear spin echoes in multidomain magnets,"By the method of additional pulsed magnetic field influence in different
+magnetic materials (half metals, manganites, lithium ferrite, cobalt) it is
+established the analogy of time diagrams of magnetic pulse influence on single-
+and two pulse echoes in magnets when the distortion mechanism of single-pulse
+echo formation is effective, and the absence of such analogy in the case of
+lithium ferrite where the multipulse mechanism of single-pulse echo formation
+is effective.
+  It is shown also that the timing and frequency diagrams of magnetic pulse
+influence on the two-pulse echo signals, corresponding to the symmetric and
+asymmetric magnetic pulse applications in the studied magnets, are defined by
+their domain walls parameters and could serve for their qualitative and
+quantitative characterization.",0705.3979v1
+2007-07-20,The Ba2LnFeNb4O15 Tetragonal Tungsten Bronze: towards RT composite multiferroics,"Several Niobium oxides of formula Ba2LnFeNb4O15 (Ln = La, Pr, Nd, Sm, Eu, Gd)
+with the Tetragonal Tungsten Bronze (TTB) structure have been synthesised by
+conventional solid-state methods. The Neodymium, Samarium and Europium
+compounds are ferroelectric with Curie temperature ranging from 320 to 440K.
+The Praseodymium and Gadolinium compounds behave as relaxors below 170 and 300
+K respectively. The Praseodymium, Neodymium, Samarium, Europium and Gadolinium
+compounds exhibit magnetic hysteresis loops at room temperature originating
+from traces of a barium ferrite secondary phase. The presence of both
+ferroelectric and magnetic hysteresis loops at room temperature allows
+considering these materials as composites multiferroic. Based on
+crystal-chemical analysis we propose some relationships between the
+introduction of Ln3+ ions in the TTB framework and the chemical, structural and
+physical properties of these materials.",0707.3112v2
+2008-08-08,Spectral properties of interacting magnetoelectric particles,"The linear magnetoelectric (ME) effect provides a special route for linking
+magnetic and electric properties. In microwaves, a local ME effect appears due
+to the dynamical symmetry breakings of magnetic-dipolar modes (MDMs) in a
+ferrite disk particle. The fact that for MDMs in a ferrite disk one has evident
+both classical and quantum-like attributes, puts special demands on the methods
+used for study of interacting ME particles. A proper model for coupled
+particles should be based on the spectral characteristics of MDM oscillations
+and an analysis of the overlap integrals for interacting eigen oscillating ME
+elements. In this paper, we present theoretical studies of spectral properties
+of literally coupled of MDM ME disks. We show that there exists the ""exchange""
+mechanism of interaction between the particles, which is distinctive from the
+magnetostatic interaction between magnetic dipoles. The spectral method
+proposed in this paper may further the development of a theory of ME
+""molecules"" and realization of local ME composites.",0808.1198v1
+2009-05-08,A simple route to a tunable electromagnetic gateway,"Transformation optics is used to design a gateway that can block
+electromagnetic waves but allows the passage of other entities. Our conceptual
+device has the advantage that it can be realized with simple materials and
+structural parameters and can have a reasonably wide bandwidth. In particular,
+we show that our system can be implemented by using a magnetic photonic crystal
+structure that employs a square ray of ferrite rods, and as the field response
+of ferrites can be tuned by external magnetic fields, we end up with an
+electromagnetic gateway that can be open or shut using external fields. The
+functionality is also robust against the positional disorder of the rods that
+made up the photonic crystal.",0905.1273v1
+2010-06-25,Epitaxial strain effects in the spinel ferrites CoFe2O4 and NiFe2O4 from first principles,"The inverse spinels CoFe2O4 and NiFe2O4, which have been of particular
+interest over the past few years as building blocks of artificial multiferroic
+heterostructures and as possible spin-filter materials, are investigated by
+means of density functional theory calculations. We address the effect of
+epitaxial strain on the magneto-crystalline anisotropy and show that, in
+agreement with experimental observations, tensile strain favors perpendicular
+anisotropy, whereas compressive strain favors in-plane orientation of the
+magnetization. Our calculated magnetostriction constants $\lambda_{100}$ of
+about -220 ppm for CoFe2O4 and -45 ppm for NiFe2O4 agree well with available
+experimental data. We analyze the effect of different cation arrangements used
+to represent the inverse spinel structure and show that both LSDA+U and GGA+U
+allow for a good quantitative description of these materials. Our results open
+the way for further computational investigations of spinel ferrites.",1006.5080v1
+2010-10-09,Superparamagnetism in Nanocrystalline Copper Ferrite Thin Films,"The rf sputtered copper ferrite films contain nanocrystalline grains. In
+these films, the magnetization does not saturate even in high magnetic fields.
+This phenomenon of high field susceptibility is attributed to the defects
+and/or superparamagnetic grains in the films. A simple model is developed to
+describe the observed high field magnetization behavior of these films. The
+model is found to fit well to the high field part for all the studied films. An
+attempt is also made to explain the temperature variation of the ferrimagnetic
+contribution on the basis of reported exchange constants.",1010.1877v1
+2010-10-09,The High Field Magnetization in the RF Sputter Deposited Copper Ferrite Thin Films,"Copper ferrite thin films were deposited on amorphous quartz substrates. The
+as deposited films were annealed in air and either quenched or slow cooled.
+Magnetization studies were carried out on the as deposited as well as annealed
+films using a SQUID magnetometer. The M-H curves were measured up to a field of
+7T, at temperatures varying from 5K to 300K. The magnetization in the films did
+not saturate, even at the highest field. The expression, M(H)= Q(1- a/H^n)
+fitted the approach to saturation best with n=1/2, for all films and at all
+temperatures. The coefficient a was the highest for the as deposited film and
+was the smallest for the quenched film. In the case of as deposited film, the
+value of coefficient a increased with increasing temperature, while for the
+annealed films, the value of a showed a decrease as temperature increases.",1010.1881v1
+2010-10-09,Temperature dependence of Magnetic properties in Nanocrystalline copper ferrite thin films,"The copper ferrite thin films have been deposited by RF sputtering at a 50W
+rf power. The As-deposited films are annealed in air at $800^{\circ}$C and then
+slow cooled. The As-deposited (AD) as well as slow cooled (SC) films are
+studied using a SQUID Magnetometer. The M Vs H curves have been recorded at
+various temperatures between 5K to 300K. The coercivities obtained from the MH
+curves are then plotted against temperature (T). The magnetization in the films
+does not saturate, even at the highest field of 7T. The high field part of the
+M Vs H curves is fitted using the H1/2 term of Chikazumi expression M(H)= Q*(1-
+a /Hn), with n=1/2. The variation of coefficient 'a' of H1/2 term has been
+observed with temperature (T). An attempt has been made to correlate this with
+the coercivity (Hc) in the case of annealed films.",1010.1882v1
+2011-03-15,Oxygen hyperstoichiometric hexagonal ferrite CaBaFe4O7+δ(δ \approx 0.14) : coexistence of ferrimagnetism and spin glass behavior,"An oxygen hyperstoichiometric ferrite CaBaFe4O7+\delta (\delta \approx 0.14)
+has been synthesized using ""soft"" reduction of CaBaFe4O8. Like the oxygen
+stoichiometric ferrimagnet CaBaFe4O7, this oxide also keeps the hexagonal
+symmetry (space group: P63mc), and exhibits the same high Curie temperature of
+270 K. However, the introduction of extra oxygen into the system weakens the
+ferrimagnetic interaction significantly at the cost of increased magnetic
+frustration at low temperature. Moreover, this canonical spin glass (Tg ~ 166
+K) exhibits an intriguing cross-over from de Almeida-Thouless type to
+Gabay-Toulouse type critical line in the field temperature plane above a
+certain field strength, which can be identified as the anisotropy field. Domain
+wall pinning is also observed below 110 K. These results are interpreted on the
+basis of cationic disordering on the iron sites.",1103.2939v1
+2011-04-08,Magnetic nanocomposites at microwave frequencies,"Most conventional magnetic materials used in the electronic devices are
+ferrites, which are composed of micrometer-size grains. But ferrites have small
+saturation magnetization, therefore the performance at GHz frequencies is
+rather poor. That is why functionalized nanocomposites comprising magnetic
+nanoparticles (e.g. Fe, Co) with dimensions ranging from a few nm to 100 nm,
+and embedded in dielectric matrices (e.g. silicon oxide, aluminium oxide) have
+a significant potential for the electronics industry. When the size of the
+nanoparticles is smaller than the critical size for multidomain formation,
+these nanocomposites can be regarded as an ensemble of particles in
+single-domain states and the losses (due for example to eddy currents) are
+expected to be relatively small. Here we review the theory of magnetism in such
+materials, and we present a novel measurement method used for the
+characterization of the electromagnetic properties of composites with
+nanomagnetic insertions. We also present a few experimental results obtained on
+composites consisting of iron nanoparticles in a dielectric matrix.",1104.1535v1
+2011-06-29,Effect of epitaxial strain on the cation distribution in spinel ferrites CoFe2O4 and NiFe2O4: a density functional theory study,"The effect of epitaxial strain on the cation distribution in spinel ferrites
+CoFe2O4 and NiFe2O4 is investigated by GGA+U total energy calculations. We
+obtain a very strong (moderate) tendency for cation inversion in NiFe2O4
+(CoFe2O4), in agreement with experimental bulk studies. This preference for the
+inverse spinel structure is reduced by tensile epitaxial strain, which can lead
+to strong sensitivity of the cation distribution on specific growth conditions
+in thin films. Furthermore, we obtain significant energy differences between
+different cation arrangements with the same degree of inversion, providing
+further evidence for recently proposed short range B site order in NiFe2O4.",1106.5887v2
+2011-08-13,First Principle Study of Magnetism and Magneto-structural Coupling in Gallium Ferrite,"We report a first-principles study of the magnetic properties, site disorder
+and magneto-structural coupling in multiferroic gallium ferrite (GFO) using
+local spin density approximation (LSDA+U) of density functional theory. The
+calculations of the ground state A-type antiferromagnetic structure predict
+magnetic moments consistent with the experiments whilst consideration of
+spin-orbit coupling yields a net orbital moment of ~ 0.025 Bohr magneton/Fe
+site also in good accordance with the experiments. We find that though site
+disorder is not spontaneous in the ground state, interchange between Fe2 and
+Ga2 sites is most favored in the disordered state. The results show that
+ferrimagnetism in GFO is due to Ga-Fe site disordering such that Fe spins at
+Ga1 and Ga2 sites are antiferromagnetically aligned while maintaining
+ferromagnetic coupling between Fe spins at Ga1 and Fe1 sites as well as between
+Fe spins at Ga2 and Fe2 sites. The effect of spin configuration on the
+structural distortion clearly indicates presence of magneto-structural coupling
+in GFO.",1108.2773v1
+2011-09-29,Ratchet effects for paramagnetic beads above striped ferrite-garnet films,"We calculate the motion of a small paramagnetic bead which is manipulated by
+the stripe domain pattern of a ferrite-garnet film. A model for the bead's
+motion in a liquid above the film is developed and used to look for ratchet
+solutions, where the bead acquires net coherent motion in one direction when
+the external field is modulated periodically. We consider three cases. First,
+the ratchet, where the beads all go in the same direction. Second, the height
+dependent ratchet, where beads at different heights go in opposite direction.
+This case can be used to separate beads of different sizes, as considered in J.
+Phys. Chem. B 112, 3833 (2008). Third, we describe how the separation threshold
+can be tuned by changing the amplitude of the applied field. Finally, we
+describe a pseudo ratchet, where the external modulation is not periodic and
+the ratchet changes direction periodically.",1109.6491v1
+2012-10-02,Magnetic Relaxation in Bismuth Ferrite Micro-Cubes,"The process of magnetic relaxation was studied in bismuth ferrite BiFeO3
+multiferroic micro-cubes obtained by means of microwave assisted Pechini
+process. Two different mechanisms of relaxation were found. The first one is a
+rapid magnetic relaxation driven by the domain reorientations and/or pinning
+and motion of domain walls. This mechanism is also responsible for the
+irreversible properties at low temperatures. The power-law decay of the
+magnetic moment confirms that this relaxation takes place in the system of
+weakly interacting ferromagnetic or superferromagnetic domains. The second
+mechanism is a longterm weak magnetic relaxation due to spin glass-phase.",1210.0765v1
+2012-12-11,Synthesis and Properties of Bismuth Ferrite Multiferroic Nanoflowers,"The method of microwave assisted hydrothermal synthesis of bismuth ferrite
+multiferroic nanoflowers, their mechanism of growth, magnetic as well as
+dielectric properties are presented. The nanoflowers are composed of numerous
+petals formed by BiFeO3 (BFO) nanocrystals and some amount of amorphous phase.
+The growth of the nanoflowers begins from the central part of calyx composed of
+only few petals towards which subsequent petals are successively attached. The
+nanoflowers exhibit enhanced magnetization due to size effect and lack of spin
+compensation in the spin cycloid. The dielectric properties of the nanoflowers
+are influenced by water confined to crystal nanovoids resulting in a broad
+dielectric permittivity maximum at 200 K {\div} 300 K and also by Polomska
+transition above the temperature of 450 K.",1212.2538v1
+2013-01-09,High coercivity induced by mechanical milling in cobalt ferrite powders,"In this work we report a study of the magnetic behavior of ferrimagnetic
+oxide CoFe2O4 treated by mechanical milling with different grinding balls. The
+cobalt ferrite nanoparticles were prepared using a simple hydrothermal method
+and annealed at 500oC. The non-milled sample presented coercivity of about 1.9
+kOe, saturation magnetization of 69.5 emu/g, and a remanence ratio of 0.42.
+After milling, two samples attained coercivity of 4.2 and 4.1 kOe, and
+saturation magnetization of 67.0 and 71.4 emu/g respectively. The remanence
+ratio MR/MS for these samples increase to 0.49 and 0.51, respectively. To
+investigate the influence of the microstructure on the magnetic behavior of
+these samples, we used X-ray powder diffraction (XPD), transmission electron
+microscopy (TEM), and vibrating sample magnetometry (VSM). The XPD analysis by
+the Williamson-Hall plot was used to estimate the average crystallite size and
+strain induced by mechanical milling in the samples.",1301.1945v1
+2013-02-05,Bulk magnetoelectricity in the hexagonal manganites and ferrites,"Improper ferroelectricity (trimerization) in the hexagonal manganites
+RMnO$_3$ leads to a network of coupled structural and magnetic vortices that
+induce domain wall magnetoelectricity and magnetization neither of which,
+however, occurs in the bulk. Here we combined first-principles calculations,
+group-theoretic techniques, and microscopic spin models to show how the
+trimerization not only induces a polarization but also a bulk magnetization and
+bulk magnetoelectric (ME) effect. This results in the existence of a bulk
+linear ME vortex structure or a bulk ME coupling such that if direction of
+polarization reverses so does magnetization. To measure the predicted ME
+vortex, we suggest RMnO$_3$ under large magnetic field. We suggest a family of
+materials, the hexagonal RFeO$_3$ ferrites, also display the predicted
+phenomena in their ground state.",1302.1099v2
+2014-02-06,Controlled growth of bismuth ferrite multiferroic flowers,"This study reports on the synthesis of ball-like bismuth ferrite BiFeO3
+nanoflowers by means of microwave assisted hydrothermal process and also on
+their composition and mechanism of growth. It turns out that the petals of the
+nanoflowers are composed of the nanocrystals with the size about 35-39 nm
+whereas their thickness and size depends on the concentration of surfactants.
+The petals contain BiFeO3 phase and traces of Bi2O3 oxide and metallic Bi and
+Fe deposited mainly at their surface. Amounts of impurity phases are more
+pronounced in nanoflowers synthesized during short time, and become almost
+negligible for longer microwave processing. The nanoflowers contain also mixed
+Fe valence, with the Fe2+/Fe3+ ratio depending on the time of synthesis. The
+growth and shape of the nanoflowers result from the process of diffusion in the
+initial stages of hydrothermal reaction.",1402.1336v1
+2014-04-10,Thermal effect on magnetic parameters of high-coercivity cobalt ferrite,"We prepared very high-coercivity cobalt ferrite nanoparticles using
+short-time high-energy mechanical milling. After the milling process, the
+coercivity of the nanoparticles reached 3.75 kOe - a value almost five times
+higher than that obtained for the non-milled sample. We performed a thermal
+treatment on the milled sample at 300, 400, and 600 oC for 30 and 180 mins, and
+studied the changes in the magnetic parameters due to the thermal treatment
+using the hysteresis curves, Williamson-Hall analysis, and transmission
+electron microscopy. The thermal treatment at 600 oC causes a decrease in the
+microstructural strain and density of structural defects resulting in a
+significant decrease in coercivity. Furthermore, this thermal treatment
+increases the size of the nanoparticles and, as a consequence, there is a
+substantial increase in the saturation magnetization. The coercivity and the
+saturation magnetization are less affected by the thermal treatment at 300 and
+400 oC.",1404.2965v1
+2014-11-06,Giant magnetodielectric metamaterial,"Dielectric materials with tunable permittivity are highly desirable for
+wireless communication, radar technology. However, the tunability of dielectric
+properties in the microwave frequency range and higher is an immense challenge
+for conventional materials. Here, we demonstrate a giant magnetodielectric
+effect in the GHz region in a metamaterial based on ferrite unit cells. The
+effect is derived from the coupling of the ferromagnetic resonance and the Mie
+resonance in the ferrite unit cells. Both the simulated and experimental
+results indicate that the effective permittivity of the metamaterial can be
+tuned by modifying the applied magnetic field, and a giant magnetodielectric
+effect, [{\epsilon}'(H) - {\epsilon}'(0)]/{\epsilon}'(0) = 15000 % at 11.284
+GHz, is obtained. This mechanism offers a promising means of constructing
+microwave dielectrics with large tunable ranges and considerable potential for
+tailoring via a metamaterial route.",1411.1470v1
+2014-11-29,Gyrotropic-nihility state in a composite ferrite-semiconductor structure,"Characteristics of the gyrotropic-nihility state are studied in a
+finely-stratified ferrite-semiconductor structure, which is under an action of
+an external static magnetic field. Investigations are carried out with the
+assistance of the effective medium theory, according to which the studied
+structure is approximated as a uniform gyroelectromagnetic medium. The theory
+of the gyrotropic-nihility state is developed in terms of the eigenwaves
+propagation in such gyroelectromagnetic medium. The frequency and angular
+dependencies of the transmittance, reflectance and absorption coefficient are
+presented. It turns out that in the frequency band around the frequency of
+gyrotropic-nihility state the studied structure appears to be matched to free
+space with both the refractive index and the wave impedance which results in
+its high transmittance almost in the entire range of angles of the
+electromagnetic wave incidence.",1412.0097v1
+2015-03-31,Ultrafast near infrared photoinduced absorption in a multiferroic single crystal of bismuth ferrite,"We studied the ultrafast third-order optical nonlinearity in a single crystal
+of multiferroic bismuth ferrite (BiFeO3) in the near-infrared range of 0.5-1.0
+eV, where the material is fundamentally transparent,at room temperature. With
+pump pulses at 1.55 eV, which is off-resonant to the strong inter-band charge
+transfer (CT) transition, we observed instantaneous transient absorption with
+pencil-like temporal profile originating from the two-photon CT transition from
+the oxygen 2p to the iron 3p levels. In contrast, under pumping with 3.10-eV
+photons, the pencil-like absorption change was not observed but decay profiles
+showed longer time constants. Although the two-photon absorption coefficient is
+estimated to be 1.5 cm/GW, which is ten (hundred) times smaller than that of
+two(one)-dimensional cuprates, it is larger than those of common semiconductors
+such as ZnSe and GaAs at the optical communication wavelength.",1503.08976v1
+2015-06-01,Evaluation of (BH)max and magnetic anisotropy of cobalt ferrite nanoparticles synthesized in gelatin,"CoFe2O4 nanoparticles were synthesized using gelatin as a polymerizing agent.
+Structural, morphological and magnetic properties of samples treated at
+different temperatures were investigated by X-ray diffraction, scanning
+electron microscopy, Mossbauer spectroscopy and magnetization measurements. Our
+results revealed that the samples annealed at 623 K and temperatures above 973
+K have a cation distributions given by (Co0.19Fe0.81)[Co0.81Fe1.19]O4 and
+(Co0.06Fe0.94)[Co0.94Fe1.06]O4, respectively. The particle sizes varied from 73
+to 296 nm and the magnetocrystalline anisotropy, K1, has values ranging from
+2.60x10^6 to 2.71x10^6 J/m3, as determined from the law of approach to
+saturation applied to the MxH data at high field. At 5 K, the saturation
+magnetization, coercive field and (BH)max varied from 76 to 95 Am2/kg, 479.9 to
+278.5 kA/m and 9.7 to 20.9 kJ/m3, respectively. The reported values are in good
+agreement with near-stoichiometric cobalt ferrite samples.",1506.00505v1
+2015-06-20,Effect of Sintering Temperature on Structural and Magnetic Properties of Ni0.6Zn0.4Fe2O4 Ferrite: Synthesized from Nanocrystalline Powders,"The effect of sintering temperatures (Ts) on the structural and magnetic
+properties of Ni0.6Zn0.4Fe2O4 (NZFO) ferrites synthesized by conventional
+double sintering method has been reported. The samples are sintered at 1200,
+1250 and 1300 {\deg}C. The X-ray diffraction (XRD) analysis reveals the
+formation of a single phase cubic spinel structure of the sample. The magnetic
+parameters such as saturation magnetization, Ms; coercive field, Hc; remanent
+magnetization, Mr and Bohr magneton, {\mu}B are determined and well compared
+with reported values. The obtained values are found to be 71.94 emu/gm and 1.2
+Oe for Ms and Hc, respectively at Ts=1300 oC. Curie temperature (Tc) at various
+Ts has also been calculated. It is noteworthy to note that the sample with a
+very low Hc could be used in transformer core and inductor applications.",1506.06280v2
+2015-06-25,Topological magnetoelectric effects in microwave far-field radiation,"Similar to electromagnetism, described by the Maxwell equations, the physics
+of magnetoelectric (ME) phenomena deals with the fundamental problem of the
+relationship between electric and magnetic fields. Despite a formal resemblance
+between the two notions, they concern effects of different natures. In general,
+ME coupling effects manifest in numerous macroscopic phenomena in solids with
+space and time symmetry breakings. Recently it was shown that the near fields
+in the proximity of a small ferrite particle with magnetic dipolar mode (MDM)
+oscillations have the space and time symmetry breakings and topological
+properties of these fields are different from topological properties of the
+free space electromagnetic (EM) fields. Such MDM originated fields, called
+magnetoelectric (ME) fields, carry both spin and orbital angular momentums.
+They are characterized by power flow vortices and non zero helicity. In this
+paper, we report on observation of the topological ME effects in far field
+microwave radiation based on a small microwave antenna with a MDM ferrite
+resonator. We show that the microwave far-field radiation can be manifested
+with a torsion structure where an angle between the electric and magnetic field
+vectors varies. We discuss the question on observation of the regions of
+localized ME energy in far field microwave radiation.",1506.07684v1
+2015-08-23,A study of the physical properties of single crystalline Fe5B2P,"Single crystals of Fe5B2P were grown by self-flux growth technique.
+Structural and magnetic properties are studied. The Curie temperature of Fe5B2P
+is determined to be 655$pm$2K. The saturation magnetization is determined to be
+1.72 MuB/Fe at 2K. The temperature variation of the anisotropy constant K1 is
+determined for the first time, reaching ~0.50 MJ/m3 at 2K, and it is comparable
+to that of hard ferrites. The saturation magnetization is found to be larger
+than the hard ferrites. The first principle calculations of saturation
+magnetization and anisotropy constant are found to be consistent with the
+experimental results.",1508.05629v1
+2015-11-04,Numerical Calculations of Wake Fields and Impedances of LHC Collimators' Real Structures,"The LHC collimators have very complicated mechanical designs including
+movable jaws made of higly resistive materials, ferrite materials, tiny RF
+contacts. Since the jaws are moved very close to the circulating beams their
+contribution in the overall LHC coupling impedance is dominant, with respect to
+other machine components. For these reasons accurate simulation of collimators'
+impedance becomes very important and challenging. Besides, several dedicated
+tests have been performed to verify correct simulations of lossy dispersive
+material properties, such as resistive wall and ferrites, benchmarking code
+results with analytical, semi-analytical and other numerical codes outcomes.
+Here we describe all the performed numerical tests and discuss the results of
+LHC collimators' impedances and wake fields calculations.",1511.01236v1
+2016-02-22,Flexible heat-flow sensing sheets based on the longitudinal spin Seebeck effect using one-dimensional spin-current conducting films,"We demonstrated a flexible thermoelectric (TE) sheet based on the
+longitudinal spin Seebeck effect (LSSE) that is especially suitable for
+heat-flow sensing applications. This TE sheet contained a Ni0.2Zn0.3Fe2.5O4
+film which was formed on a flexible plastic sheet using a spray-coating method
+known as ferrite plating. The experimental results suggest that the
+ferrite-plated film, which has a columnar crystal structure aligned
+perpendicular to the film plane, functions as a unique one-dimensional
+spin-current conductor suitable for bendable LSSE-based sensors.",1602.06684v1
+2016-02-26,Water dispersible CoFe2O4 nanoparticles with improved colloidal stability for biomedical applications,"Single phase cobalt ferrite (CoFe2O4, CFO) nanoparticles of a controlled size
+(~ 6 nm) exhibiting superparamagnetic properties have been synthesized by
+hydrothermal technique using oleic acid (OA) as surfactant. The oleic acid
+coated CFO nanoparticles are stable in non-polar organic media, such as hexane
+but are not well dispersible in water. The surface of these snanoparticles has
+been further modified by citric acid using ligand exchange process, which makes
+CFO nanoparticles more stable colloidal solution in water. Citric acid coated
+CFO nanoparticles exhibits high dispersibility in water, high zeta potential,
+very low coercivity and moderate saturation magnetization. Biocompatibility of
+these CFO nanoparticles is demonstrated through cytotoxicity test in L929 cell
+line.",1602.08415v1
+2016-03-16,Molecular dynamics simulation of nanoindentation on nanocomposite pearlite,"We carry out molecular dynamics simulations of nanoindentation to investigate
+the effect of cementite size and temperature on the deformation behavior of
+nanocomposite pearlite composed of alternating ferrite and cementite layers. We
+find that, instead of the coherent transmission, dislocation propagates by
+forming a widespread plastic deformation in cementite layer. We also show that
+increasing temperature enhances the distribution of plastic strain in the
+ferrite layer, which reduces the stress acting on the cementite layer. Hence,
+thickening cementite layer or increasing temperature reduces the likelihood of
+dislocation propagation through the cementite layer. Our finding sheds a light
+on the mechanism of dislocation blocking by cementite layer in the pearlite.",1603.05153v1
+2016-07-10,Effect of isothermal holding temperature on the precipitation hardening in Vanadium-microalloyed steels with varying carbon and nitrogen levels,"Combined effect of Carbon and Nitrogen levels and isothermal holding
+temperature on the microstructure, precipitation and the tensile properties of
+Vanadium microalloyed steels with 0.05 weight percent Vanadium were studied.
+Two different Vanadium steels, one having higher Carbon and lower Nitrogen
+content, HCLN steel, and the other having lower Carbon and higher Nitrogen
+content, LCHN steel, were prepared and subjected to isothermal holding
+treatment over a temperature range of 500 to 750 degree Celsius, after
+hot-deformation. Maximum precipitation strengthening from fine Vanadium
+carbonitride precipitates has been found at intermediate isothermal holding
+temperatures i.e. 600 to 650 degree Celsius in both the steels. In spite of the
+significantly smaller fraction of pearlite and bainite, coarser average ferrite
+grain size and lower interaction of precipitation and dislocation in the
+ferrite matrix, the yield strength of LCHN steel was close to HCLN steel. This
+can be attributed to the higher precipitation strengthening ranging from 20 to
+50 MPa resulted from the finer Vanadium precipitates in LCHN steel than that of
+HCLN steel.",1607.02721v1
+2016-10-07,Performance Evaluation of Klystron Beam Focusing System with Anisotropic Ferrite Magnet,"A klystron beam focusing system using permanent magnets, which increases
+reliability in comparison with electromagnet focusing system, is reported. A
+prototype model has been designed and fabricated for a 1.3 GHz, 800 kW klystron
+for evaluation of the feasibility of the focusing system with permanent
+magnets. In order to decrease the production cost and to mitigate complex
+tuning processes of the magnetic field, anisotropic ferrite magnet is adopted
+as the magnetic material. As the result of a power test, 798 kW peak output
+power was successfully achieved with the prototype focusing system. Considering
+a power consumption of the electromagnet focusing system, the required
+wall-plug power to produce nominal 800 kW output power with the permanent
+magnet system is less than that with electromagnet. However, the power
+conversion efficiency of the klystron with the permanent magnet system was
+found to be limited by transverse multipole magnetic fields. By decreasing
+transverse multipole magnetic field components, especially the dipole and the
+quadrupole, the power conversion efficiency would approach to that with
+electromagnets.",1610.02130v1
+2017-02-20,Effect of annealing on the magnetic properties of zinc ferrite thin films,"We report on the magnetic properties of zinc ferrite thin film deposited on
+SrTiO$_3$ single crystal using pulsed laser deposition. X-ray diffraction
+result indicates the highly oriented single phase growth of the film along with
+the presence of the strain. In comparison to the bulk antiferromagnetic order,
+the as-deposited film has been found to exhibit ferrimagnetic ordering with a
+coercive field of 1140~Oe at 5~K. A broad maximum, at $\approx$105~K, observed
+in zero-field cooled magnetization curve indicates the wide grain size
+distribution for the as-deposited film. Reduction in magnetization and blocking
+temperature has been observed after annealing in both argon as well as oxygen
+atmospheres, where the variation was found to be dependent on the annealing
+temperature.",1702.06033v1
+2018-11-12,Current direction anisotropy of the spin Hall magnetoresistance in nickel ferrite thin films with bulk-like magnetic properties,"We utilize spin Hall magnetoresistance (SMR) measurements to experimentally
+investigate the pure spin current transport and magnetic properties of nickel
+ferrite (NiFe2O4,NFO)/normal metal (NM) thin film heterostructures. We use
+(001)-oriented NFO thin films grown on lattice-matched magnesium gallate
+substrates by pulsed laser deposition, which significantly improves the
+magnetic and structural properties of the ferrimagnetic insulator. The NM in
+our experiments is either Pt or Ta. A comparison of the obtained SMR magnitude
+for charge currents applied in the [100]- and [110]-direction of NFO yields a
+change of 50% for Pt at room temperature. We also investigated the temperature
+dependence of this current direction anisotropy and find that it is
+qualitatively different for the conductivity and the SMR magnitude. From our
+results we conclude that the observed current direction anisotropy may
+originate from an anisotropy of the spin mixing conductance or of the spin Hall
+effect in these Pt and Ta layers, and/or additional spin-galvanic contributions
+from the NFO/NM interface.",1811.04696v1
+2020-07-28,Magnetic bubbles in an M-type hexagonal ferrite observed by hollow-cone Foucault imaging and small-angle electron diffraction,"We report hollow-cone imaging and small-angle electron diffraction of
+nanoscale magnetic textures such as magnetic-striped domains and magnetic
+bubbles of M-type hexagonal ferrite
+BaFe$_{10.35}$Sc$_{1.6}$Mg$_{0.05}$O$_{19}$. The advantage of the hollow-cone
+Foucault method is that magnetic domains with various directions of
+magnetization can be visualized under an infocus condition. Moreover, the
+contrast of magnetic domain walls in magnetic bubbles depends on the
+inclination angle of the illumination beam. The combination of small-angle
+electron diffraction and hollow-cone Foucault imaging proves that magnetization
+at domain walls exhibits in-plane directions in the magnetic-striped domains
+and magnetic bubbles.",2007.13994v1
+2016-11-29,Superdirectional Beam of Surface Spin Wave,"The visualized diffraction patterns of surface spin wave excited by
+arbitrarily oriented linear transducer are investigated experimentally in the
+plane of tangentially magnetized ferrite film for the case where the transducer
+length D is much larger than the wavelength L. It is shown experimentally and
+theoretically that the angular width of diffracted surface spin wave beam in
+anisotropic ferrite film can take values greater or less than L/D and can also
+be zero. For the last case superdirectional (nonexpanding) beam of the surface
+spin wave is observed experimentally: the smearing of the beam energy along the
+film plane is absent and the length of the beam trajectory is maximal (~50 mm).",1611.09595v2
+2018-05-10,Maximizing Specific Loss Power for Magnetic Hyperthermia by Hard-Soft Mixed Ferrites,"We report maximized specific loss power and intrinsic loss power approaching
+theoretical limits for AC magnetic field heating of nanoparticles. This is
+achieved by engineering the effective magnetic anisotropy barrier of
+nanoparticles via alloying of hard and soft ferrites. 22 nm
+Co0.03Mn0.28Fe2.7O4/SiO2 NPs reached a specific loss power value of 3417
+W/gmetal at a field of 33 kA/m and 380 kHz. Biocompatible Zn0.3Fe2.7O4/SiO2
+nanoparticles achieved specific loss power of 500 W/gmetal and intrinsic loss
+power of 26.8 nHm2/kg at field parameters of 7 kA/m and 380 kHz, below the
+clinical safety limit. Magnetic bone cement achieved heating adequate for bone
+tumor hyperthermia, incorporating ultralow dosage of just 1 wt% of
+nanoparticles. In cellular hyperthermia experiments, these nanoparticles
+demonstrated high cell death rate at low field parameters. Zn0.3Fe2.7O4/SiO2
+nanoparticles show cell viabilities above 97% at concentrations up to 0.5 mg/ml
+within 48 hrs, suggesting toxicity lower than that of magnetite.",1805.04204v1
+2011-11-17,Field-induced Magnetic Transition in Cobalt-Ferrite,"We present magnetostriction and magnetization measurements of a cobalt
+ferrite Co0.8Fe2.2O4 single crystal. We observe unusual behaviour in the
+magnetic hard axis of the single crystal which manifests in a jump of the
+magnetization curve at a critical field. This first order magnetization process
+(FOMP) which is explained as an anisotropy driven transition is visible at
+temperatures lower than 150 K. By analyzing the anisotropy constants we found
+that the higher order anisotropy constant K2 dominates the anisotropy energy.
+In the magnetostriction measurements the FOMP is clearly visible as a huge jump
+in the [111] direction, which can be explained by means of a geometric model.",1111.4027v2
+2013-09-27,Constrained non-collinear magnetism in disordered Fe and Fe-Cr alloys,"The development of quantitative models for radiation damage effects in iron,
+iron alloys and steels, particularly for the high temperature properties of the
+alloys, requires understanding of magnetic interactions, which control the
+phase stability of ferritic-martensitic, ferritic, and austenitic steels. In
+this work, disordered magnetic configurations of pure iron and Fe-Cr alloys are
+investigated using Density Functional Theory (DFT) formalism, in the form of
+constrained non-collinear magnetic calculations, with the objective of creating
+a database of atomic magnetic moments and forces acting between the atoms. From
+a given disordered atomic configuration of either pure Fe or Fe-Cr alloy, a
+penalty contribution to the usual spin-polarized DFT total energy has been
+calculated by constraining the magnitude and direction of magnetic moments. An
+extensive database of non-collinear magnetic moment and force components for
+various atomic configurations has been generated and used for interpolating the
+spatially-dependent magnetic interaction parameters, for applications in
+large-scale spin-lattice dynamics and magnetic Monte-Carlo simulations.",1309.7183v1
+2016-08-11,A revisited Johnson-Mehl-Avrami-Kolmogorov model and the evolution of grain-size distributions in steel,"The classical Johnson-Mehl-Avrami-Kolmogorov approach for nucleation and
+growth models of diffusive phase transitions is revisited and applied to model
+the growth of ferrite in multiphase steels. For the prediction of mechanical
+properties of such steels, a deeper knowledge of the grain structure is
+essential. To this end, a Fokker-Planck evolution law for the volume
+distribution of ferrite grains is developed and shown to exhibit a log-normally
+distributed solution. Numerical parameter studies are given and confirm
+expected properties qualitatively. As a preparation for future work on
+parameter identification, a strategy is presented for the comparison of volume
+distributions with area distributions experimentally gained from polished
+micrograph sections.",1608.03821v3
+2017-06-07,PbTi1-xPdxO3: A New Room-temperature Magnetoelectric Multiferroic Device Material,"There have been a large number of papers on bismuth ferrite (BiFeO3) over the
+past few years, trying to exploit its room-temperature magnetoelectric
+multiferroic properties. Although these are attractive, BiFeO3 is not the ideal
+multiferroic, due to weak magnetization and the difficulty in limiting leakage
+currents. Thus there is an ongoing search for alternatives, including such
+materials as gallium ferrite (GaFeO3). In the present work we report a
+comprehensive study of the perovskite PbTi1-xPdxO3 with 0 < x < 0.3. Our study
+includes dielectric, impedance and magnetization measurements, conductivity
+analysis and study of crystallographic phases present in the samples with
+special attention paid to minor phases, identified as PdO, PbPdO2, and Pd3Pb.
+The work is remarkable in two ways: Pd is difficult to substitute into ABO3
+perovskite oxides (where it might be useful for catalysis), and Pd is magnetic
+under only unusual conditions (under strain or internal electric fields). The
+new material, as a PZT derivative, is expected to have much stronger
+piezoelectric properties than BiFeO3.",1706.02194v1
+2017-07-13,Towards the ab initio based theory of the phase transformations in iron and steel,"Despite of the appearance of numerous new materials, the iron based alloys
+and steels continue to play an essential role in modern technology. The
+properties of a steel are determined by its structural state (ferrite,
+cementite, pearlite, bainite, martensite, and their combination) that is formed
+under thermal treatment as a result of the shear lattice reconstruction ""gamma""
+(fcc) -> ""alpha"" (bcc) and carbon diffusion redistribution. We present a review
+on a recent progress in the development of a quantitative theory of the phase
+transformations and microstructure formation in steel that is based on an ab
+initio parameterization of the Ginzburg-Landau free energy functional. The
+results of computer modeling describe the regular change of transformation
+scenario under cooling from ferritic (nucleation and diffusion-controlled
+growth of the ""alpha"" phase to martensitic (the shear lattice instability
+""gamma"" -> ""alpha""). It has been shown that the increase in short-range
+magnetic order with decreasing the temperature plays a key role in the change
+of transformation scenarios. Phase-field modeling in the framework of a
+discussed approach demonstrates the typical transformation patterns.",1707.04287v1
+2017-07-26,"Bismuth Ferrite Dielectric Nanoparticles Excited at Telecom Wavelengths as Multicolor Sources by Second, Third, and Fourth Harmonic Generation","We demonstrate the simultaneous generation of second, third, and fourth
+harmonic from a single dielectric Bismuth Ferrite nanoparticle excited by a
+telecom fiber laser at 1560 nm. We first characterize the signals associated
+with different nonlinear orders in terms of spectrum, excitation intensity
+dependence, and relative signal strengths. Successively, on the basis of the
+polarization-resolved emission curves of the three harmonics, we discuss the
+interplay of susceptibility tensor components at the different orders and we
+show how polarization can be used as an optical handle to control the relative
+frequency conversion properties.",1707.08451v4
+2018-01-04,Properties of polycrystalline nanoparticles with uniaxial and cubic types of magnetic anisotropy of individual grains,"The influence of the crystal structure inhomogeneities on the magnetic
+properties of cobalt nanoparticles with different aspect ratio and spherical
+nanoparticles of chromium dioxide, cobalt ferrite and magnetite has been
+studied by means of numerical simulation. The polycrystalline nanoparticles are
+modeled by means of subdivision of the nanoparticle volume into tightly bound
+single-crystal granules with randomly distributed directions of the easy
+anisotropy axes. The probability of appearance of quasi uniform and vortex
+states in sufficiently large assemblies of polycrystalline nanoparticles of
+various types have been calculated depending on the nanoparticle diameter. It
+is shown that the subdivision of a nanoparticle into single-crystal granules
+with different orientations of the easy anisotropy axes substantially reduces
+the effective single-domain diameters for particles with uniaxial type of
+anisotropy of individual granules. However, for particles with cubic type of
+magnetic anisotropy the influence of the crystal structure inhomogeneities on
+the equilibrium properties of the particles is not so important even for
+magnetically hard cobalt ferrite nanoparticles. It is practically absent for
+magnetically soft magnetite nanoparticles.",1801.01266v1
+2019-07-01,"Structural phase diagram and magnetic properties of Sc-substituted rare earth ferrites R1-xScxFeO3 (R=Lu, Yb, Er, and Ho)","We have studied the structural stability of Sc-substituted rare earth (R)
+ferrites R1-xScxFeO3, and constructed a structural phase diagram for different
+R and x. While RFeO3 and ScFeO3 adopt the orthorhombic and the bixbyite
+structure respectively, the substituted compound R1-xScxFeO3 may be stable in a
+different structure. Specifically, for R0.5Sc0.5FeO3, the hexagonal structure
+can be stable for small R, such as Lu and Yb, while the garnet structure is
+stable for larger R, such as Er and Ho. The formation of garnet structure of
+the R0.5Sc0.5FeO3 compounds which requires that Sc occupies both the rare earth
+and the Fe sites, is corroborated by their magnetic properties.",1907.01052v1
+2019-07-15,Study of CoFe2O4/CoFe2 nanostructured powder,"We report an experimental study of the CoFe2O4/CoFe2 nanocomposite, a
+nanostructured material formed by hard (CoFe2O4) and soft (CoFe2) magnetic
+materials. The precursor material, cobalt ferrite (CoFe2O4), was prepared using
+the conventional stoichiometric gel-combustion method. The nanocomposite
+material was obtained by reducing partially the precursor material using
+activated charcoal as reducing agent in air and argon atmospheres, at 800 and
+900 C respectively. The magnetic hysteresis loops demonstrate that, in general,
+prepared nanocomposite samples display single magnetic behavior, indicating
+exchange coupling between the soft and hard magnetic phases. However, for
+nanocomposite samples prepared at higher temperatures, the hysteresis
+measurements show steps typical of two-phase magnetic behavior, suggesting the
+existence of two non-coupled magnetic phases. The studied nanocomposites
+presented coercivity (HC) of about 0.7 kOe, which is considerably lower than
+the expected value for cobalt ferrite. A huge increase in HC (>440%) and
+maximum energy product (about 240%) was obtained for the nanocomposite after
+high energy milling processing.",1907.06758v1
+2019-07-28,Warren-Averbach line broadening analysis from a time of flight neutron diffractometer,"The well known Warren-Averbach theory of diffraction line profile broadening
+is shown to be applicable to time of flight data obtained from a neutron
+spallation source. Without modification, the method is applied to two very
+different examples; a cold worked ferritic steel and a thermally stressed
+alumina-30% SiC composite. Values of root mean square strains averaged over a
+range of lengths for the ferritic steel were used to estimate dislocation
+densities; values were found to be in good agreement with geometrically
+necessary dislocation densities independently measured from similarly
+orientated grains measured from electron backscatter diffraction analysis. An
+analytical model for the ceramic is described to validate the estimate of root
+mean square strain.",1907.12076v1
+2019-10-22,"Comment on Crystallite size dependent exchange bias in MgFe2O4 thin films on Si (100), Journal of Applied Physics, volume 124, page 053901, 2018","K. Mallick and P. S. A. Kumar had reported exchange bias effect in Mg-ferrite
+thin films, deposited on Si substrate (with a buffer layer of MgO) using Pulsed
+Laser Deposition (PLD) technique. The authors had presented the temperature
+dependence exchange bias effect, field dependence exchange bias effect and
+training effect of a selected Magnesium ferrite thin film of thickness 132 nm.
+These studies were followed by the film thickness dependence of exchange bias
+effect. However, the data presented for the 132 nm thick film shows mutually
+contradicting values in each and every figures. Here, I point out these highly
+self-contradicting data in this comment.",1910.10120v1
+2018-03-18,Non-reciprocal Components Based on Switched Transmission Lines,"Non-reciprocal components, such as isolators and circulators, are critical to
+wireless communication and radar applications. Traditionally, non-reciprocal
+components have been implemented using ferrite materials, which exhibit
+non-reciprocity under the influence of an external magnetic field. However,
+ferrite materials cannot be integrated into IC fabrication processes, and
+consequently are bulky and expensive. In the recent past, there has been strong
+interest in achieving non-reciprocity in a non-magnetic IC-compatible fashion
+using spatio-temporal modulation. In this paper, we present a general approach
+to non-reciprocity based on switched transmission lines. Switched transmission
+lines enable broadband, lossless and compact non-reciprocity, and a wide range
+of non-reciprocal functionalities, including non-reciprocal phase shifters,
+ultra-broadband gyrators and isolators, frequency-conversion isolators, and
+high-linearity/high-frequency/ultra-broadband circulators. We present a
+detailed theoretical analysis of the various non-idealities that impact
+insertion loss and provide design guidelines. The theory is validated by
+experimental results from discrete-component-based gyrators and isolators, and
+a 25GHz circulator fabricated in 45nm SOI CMOS technology.",1803.06690v1
+2018-06-25,Ferromagnetism above 1000 K in highly cation-ordered double-perovskite insulator Sr3OsO6,"Magnetic insulators have been intensively studied for over 100 years, and
+they, in particular ferrites, are considered to be the cradle of magnetic
+exchange interactions in solids. Their wide range of applications include
+microwave devices and permanent magnets . They are also suitable for spintronic
+devices owing to their high resistivity, low magnetic damping, and
+spin-dependent tunneling probabilities. The Curie temperature is the crucial
+factor determining the temperature range in which any ferri/ferromagnetic
+system remains stable. However, the record Curie temperature has stood for over
+eight decades in insulators and oxides (943 K for spinel ferrite LiFe5O8). Here
+we show that a highly B-site ordered double-perovskite, Sr2(SrOs)O6 (Sr3OsO6),
+surpasses this long standing Curie temperature record by more than 100 K. We
+revealed this B-site ordering by atomic-resolution scanning transmission
+electron microscopy. The density functional theory (DFT) calculations suggest
+that the large spin-orbit coupling (SOC) of Os6+ 5d2 orbitals drives the system
+toward a Jeff = 3/2 ferromagnetic (FM) insulating state. Moreover, the Sr3OsO6
+is the first epitaxially grown osmate, which means it is highly compatible with
+device fabrication processes and thus promising for spintronic applications.",1806.09308v1
+2018-06-27,Photocatalytic activity enhancement by addition of lanthanum into the BiFeO3 structure and the effect of synthesis method,"In this paper, the photocatalytic activity of multiferroics BiFeO3 (BFO) and
+Bi0.8La0.2FeO3 (BLFO) nanocrystals with two different morphologies which were
+synthesized by two different sol-gel (SG) and hydrothermal (HT) methods have
+been studied. All the obtained samples were characterized using X-ray
+diffractometer, Fourier transform infrared spectroscopy, transmission electron
+microscopy, UV-vis spectroscopy and vibrating sample magnetometer. Differential
+thermal analysis (DTA) measurements were probed ferroelectric- paraelectric
+first-order phase transition (TC) for all samples. Addition of lanthanum
+decreases the electric phase transition. For photocatalyst application of
+bismuth ferrite, adsorption potential of nanoparticles for methylene blue (MB)
+organic dye was evaluated. The doping of La in the BFO structure enhanced the
+photocatalytic activity and about 71% degradation of MB dye was obtained under
+visible irradiation. The magnetic and ferroelectric properties of BLFO
+nanoparticles improve compared to the undoped BiFeO3 nanoparticles. The
+non-saturation at high applied magnetic field for as-prepared samples by HT is
+related to the size and shape of products. This work not only presents an
+effect of lanthanum substitution into the bismuth ferrite structure on the
+physical properties of BFO, but also compares the synthesis method and its
+influence on the photocatalytic activity and multiferroics properties of all
+nanopowders.",1807.03127v1
+2018-08-25,"Photocatalytic activity, optical and ferroelectric properties of Bi0.8Nd0.2FeO3 nanoparticles synthesized by sol-gel and hydrothermal methods","In this study, the effects of synthesis method and dopant Neodymium ion on
+the ferroelectric properties and photocatalytic activity of bismuth ferrite
+were studied. BiFeO3 (BFO) and Bi0.8Nd0.2FeO3 (BNFO) nanoparticles were
+prepared through a facile sol-gel combustion (SG) and hydrothermal (HT)
+methods. The as-prepared products were characterized by X-ray powder
+diffraction (XRD), Furrier transform infrared spectroscopy (FTIR) and
+transmission electron microscope (TEM) images. Both nanophotocatalysts have
+similar crystal structures, but the SG products have semi-spherical morphology.
+On the other hand, HT samples have rod-like morphology. TEM results indicated
+that the morphology of products was not affected by the doping process. The
+thermal, optical and magnetic properties of nanoparticles were investigated by
+thermogravitometry and differential thermal analysis (TG/DTA), UV-vis
+spectroscopy, and vibrating sample magnetometer (VSM). The ferroelectric
+properties of BNFO nanoparticles were improved compared to the undoped bismuth
+ferrite. The photocatalytic activity of as-synthesized nanoparticles was also
+evaluated by the degradation of methyl orange (MO) under visible light
+irradiation. The photocatalytic activity of nanoparticles prepared via sol-gel
+method exhibited a higher photocatalytic activity compared to powders obtained
+by hydrothermal method. Also substitution of Nd into the BFO structure
+increased the photocatalytic activity of products.",1808.08427v1
+2019-04-04,A highly accurate determination of absorbed power during nanomagnetic hyperthermia,"Absorbed power of nanoparticles during magnetic hyperthermia can be well
+determined from changes in the quality factor ($Q$ factor) of a resonator, in
+which the radiofrequency (RF) absorbent is placed. We present an order of
+magnitude improvement in the $Q$ factor measurement accuracy over conventional
+methods by studying the switch-on and off transient signals of the resonators.
+A nuclear magnetic resonance (NMR) console is ideally suited to acquire the
+transient signals and it also allows to employ the so-called pulse
+phase-cycling to remove transient artifacts. The improved determination of the
+absorbed power is demonstrated on various resonators in the 1-30 MHz range
+including standard solenoids and also a birdcage resonator. This leads to the
+possibility to detect minute amounts of ferrite nanoparticles which are
+embedded in the body and also the amount of the absorbed power. We demonstrate
+this capability on a phantom study, where the exact location of an embedded
+ferrite is clearly detected.",1904.02360v1
+2019-08-01,Size-dependent spatial magnetization profile of manganese-zinc ferrite Mn0.2Zn0.2Fe2.6O4 nanoparticles,"We report the results of an unpolarized small-angle neutron scattering (SANS)
+study on Mn-Zn ferrite (MZFO) magnetic nanoparticles with the aim to elucidate
+the interplay between their particle size and the magnetization configuration.
+We study different samples of single-crystalline MZFO nanoparticles with
+average diameters ranging between 8 to 80 nm, and demonstrate that the smallest
+particles are homogeneously magnetized. However, with increasing nanoparticle
+size, we observe the transition from a uniform to a nonuniform magnetization
+state. Field-dependent results for the correlation function confirm that the
+internal spin disorder is suppressed with increasing field strength. The
+experimental SANS data are supported by the results of micromagnetic
+simulations, which confirm an increasing inhomogeneity of the magnetization
+profile of the nanoparticle with increasing size. The results presented
+demonstrate the unique ability of SANS to detect even very small deviations of
+the magnetization state from the homogeneous one.",1908.00343v2
+2019-08-07,Fast response of pulsed laser deposited Zinc ferrite thin film as a chemo-resistive gas sensor,"Thin films of ZnFe2O4 deposited by pulsed laser technique are here
+demonstrated as one of the interesting materials for sensing of ethanol. The
+response transients were fitted well to one-site Langmuir adsorption model.
+Activation energies for (I) adsorption and reaction of ethanol and (II)
+desorption (i.e. recovery process) of ethanol from zinc ferrite thin film
+surface were obtained on the basis of this model. In this paper, we showed the
+effect of operating temperature and gas-concentration on the response time of
+thin film sensor materials. At the operating temperature 340oC, the ZnFe2O4
+thin film showed high (84%) as well as immediate response to 500 ppm of
+ethanol, with its resistance being saturated within ~12 seconds, which stands
+far superior to the response time of nano crystalline powders. Those films were
+also observed to have a good repeatability of their sensor response, thus
+representing a major step towards low-cost large-scale production of this class
+of devices.",1908.02780v1
+2021-06-21,A low-loss ferrite circulator as a tunable chiral quantum system,"Ferrite microwave circulators allow one to control the directional flow of
+microwave signals and noise, and thus play a crucial role in present-day
+superconducting quantum technology. They are typically viewed as a black-box,
+and their internal structure is not specified, let alone used as a resource. In
+this work, we demonstrate a low-loss waveguide circulator constructed with
+single-crystalline yttrium iron garnet (YIG) in a 3D cavity, and analyze it as
+a multi-mode hybrid quantum system with coupled photonic and magnonic
+excitations. We show the coherent coupling of its chiral internal modes with
+integrated superconducting niobium cavities, and how this enables tunable
+non-reciprocal interactions between the intra-cavity photons. We also probe
+experimentally the effective non-Hermitian dynamics of this system and its
+effective non-reciprocal eigenmodes. The device platform provides a test bed
+for implementing non-reciprocal interactions in open-system circuit QED.",2106.11283v2
+2021-12-23,Control of site occupancy by variation of the Zn and Al content in NiZnAl ferrite epitaxial films with low magnetic damping,"The structural and magnetic properties of Zn/Al doped nickel ferrite thin
+films can be adjusted by changing the Zn and Al content. The films are
+epitaxially grown by reactive magnetron sputtering using a triple cluster
+system to sputter simultaneously from three different targets. Upon the
+variation of the Zn content the films remain fully strained with similar
+structural properties, while the magnetic properties are strongly affected. The
+saturation magnetization and coercivity as well as resonance position and
+linewidth from ferromagnetic resonance (FMR) measurements are altered depending
+on the Zn content in the material. The reason for these changes can be
+elucidated by investigation of the x-ray magnetic circular dichroism spectra to
+gain site and valence specific information with elemental specificity.
+Additionally, from a detailed investigation by broadband FMR a minimum in
+g-factor and linewidth could be found as a function of film thickness.
+Furthermore, the results from a variation of the Al content using the same set
+of measurement techniques is given. Other than for Zn, the variation of Al
+affects the strain and even more pronounced changes to the magnetic properties
+are apparent.",2112.12456v1
+2022-01-12,Magnetic domain wall pinning in cobalt ferrite microstructures,"A detailed correlative structural, magnetic and chemical analysis of
+non-stoichiometric cobalt ferrite micrometric crystals was performed by x-ray
+magnetic circular dichroism combined with photoemission microscopy, low energy
+electron microscopy, and atomic force microscopy. The vector magnetization at
+the nanoscale is obtained from magnetic images at different x-ray incidence
+angles and compared with micromagnetic simulations, revealing the presence of
+defects which pin the magnetic domain walls. A comparison of different types of
+defects and the domain walls location suggests that the main source of pinning
+in these microcrystals are linear structural defects induced in the spinel by
+the substrate steps underneath the islands.",2201.04384v1
+2022-01-18,Growth and characterization of ultrathin cobalt ferrite films on Pt(111),"CoFe2O4 thin films (5 nm and 20 nm thick) were grown by oxygen assisted
+molecular beam epitaxy on Pt(111) at 523~K and subsequently annealed at 773 K
+in vacuum or oxygen. They were characterized in-situ using Auger Electron
+Spectroscopy, Low-Energy Electron Diffraction, Scanning Tunneling Microscopy
+and Conversion Electron M\""ossbauer Spectroscopy. The as-grown films were
+composed of small, nanometric grains. Annealing of the films produced an
+increase in the grain size and gave rise to magnetic order at room temperature,
+although with a fraction of the films remaining in the paramagnetic state.
+Annealing also induced cobalt segregation to the surface of the thicker films.
+The measured M\""ossbauer spectra at low temperature were indicative of cobalt
+ferrite, the both films showing very similar hyperfine patterns. Annealing in
+oxygen or vacuum affected the cationic distribution, which was closer to that
+expected for an inverse spinel in the case of annealing in an oxygen
+atmosphere.",2201.07087v1
+2022-04-15,Experimental Visualization of Dispersion Characteristics of Backward Volume Spin Wave Modes,"Basing on the measurement of spatial spectra (spectra of wavenumbers), the
+dispersion characteristics of the first three modes of backward volume spin
+wave, propagating along the direction of a constant uniform magnetic field in a
+tangentially magnetized ferrite film, were visualized firstly. The study was
+carried out by microwave probing of spin waves with subsequent use of spatial
+Fourier analysis of the complex wave amplitude for a series of frequencies. It
+was found that every m-th mode of the backward volume spins wave can be split
+into n satellite modes due to the existence of layers with similar magnetic
+parameters in ferrite film. It was found that satellites of the first mode of
+this wave are excited most effectively, while satellites of the third mode -
+least effectively, and the effectiveness of satellites excitation decreases as
+the number n increases. It is found that the theoretical dispersion
+dependencies of the first three modes of the wave coincide well with the
+experimental dispersion dependencies of the satellite mode that are excited
+most effectively.",2204.08293v1
+2022-09-19,Ferroelectric Solitons Crafted in Epitaxial Bismuth Ferrite Superlattices,"In ferroelectrics, complex interactions among various degrees of freedom
+enable the condensation of topologically protected polarization textures. Known
+as ferroelectric solitons, these particle-like structures represent a new class
+of materials with promise for beyond CMOS technologies due to their ultrafine
+size and sensitivity to external stimuli. Such polarization textures have
+scarcely been reported in multiferroics. Here, we report a range of soliton
+topologies in bismuth ferrite strontium titanate superlattices. High-resolution
+piezoresponse force microscopy and Cs-corrected high-angle annular dark-field
+scanning transmission electron microscopy reveal a zoo of topologies, and
+polarization displacement mapping of planar specimens reveals center-convergent
+and divergent topological defects as small as 3 nm. Phase field simulations
+verify that some of these topologies can be classed as bimerons, with a
+topological charge of plus and minus one, and first-principles-based effective
+Hamiltonian computations show that the co-existence of such structures can lead
+to non-integer topological charges, a first observation in a BiFeO3-based
+system. Our results open new opportunities in multiferroic topotronics.",2209.08979v1
+2022-12-30,Preparation of CuxCe$_{0.3-X}$Ni$_{0.7}$Fe$_2$O$_4$ ferrite nanoparticles as a nitrogen dioxide gas sensor,"In this work, the ferrite nanocomposite CuxCe$_{0.3-X}$Ni$_{0.7}$Fe$_2$O$_4$
+is prepared (where: x = 0, 0.05, 0.1, 0.15, 0.2, 0.25) was prepared using the
+auto combustion technique (sol-gel), and citric acid was utilized as the fuel
+for Auto combustion. The results of X-ray diffraction (XRD), emitting field
+scanning electron microscope (FE-SEM), and energy dispersive X-ray analyzer
+(EDX) tests revealed that the prepared compound has a face-centered cubic
+structure (FCC) polycrystalline, and the lattice constant increases with an
+increase in the percentage of doping for the copper ion, and decreases for the
+cerium ion and that the compound is porous, and its molecules are spherical,
+and there are no additional elements present other than those used in the
+synthesis of the compound, indicating that it is of high purity, and the
+combination has a high sensitivity to Nitrogen dioxide (NO$_2$) gas, as
+determined by the gas detecting equipment.",2212.14861v1
+2023-01-26,"Magnetic, Optoelectronic, and Rietveld refined structural properties of Al3+ substituted nanocrystalline Ni-Cu spinel ferrites: An experimental and DFT based study","The nanocrystalline Ni0.7Cu0.3AlxFe2-xO4 (x=0.00: 0.02: 0.10) is prepared
+through the sol-gel autocombustion route.Both XRD and Rietveld confirm the
+single-phase cubic spinel structure of the investigated materials.Other
+structural parameters refined by the Rietveld refinement analysis are
+corroborated to single-phase cubic spinel formation of the NPs.Leveraging a
+vibrating sample magnetometer (VSM) the consequence of Al3+ substitution on the
+magnetic parameters is studied.The saturation magnetization (MS) and Bohr
+magneton are found to decrease with Al3+ substitution.The Remanence ratio and
+coercivity (HC) are observed to be very low suggesting the materials are soft
+ferromagnetic.First-principle calculations were carried out using the density
+functional theory (DFT) to demonstrate the optoelectronic behavior of the
+materials.The electronic bandgap is found low as Eg=2.99eV for the explored
+materials with observing defect states at 0.62eV.The optoelectronic properties
+of Al3+ substituted Ni-Cu ferrite NPs have been characterized through the DFT
+simulation for the first time, demonstrating their potentiality for
+optoelectronic device applications.The materials' optical anisotropy is
+observed along the x-axis, which manifests their tunability through
+light-matter interaction.",2301.11373v1
+2023-01-21,Synthesis and characterization of PEG-coated Zn$_{0.3}$Mn$_x$Fe$_{2.7-x}$O$_4$ nanoparticles as the dual T1/T2-weighted MRI contrast agent,"Super-paramagnetic nanoparticles (NPs) have been widely explored as magnetic
+resonance imaging (MRI) contrast agents because of a combination of favorable
+magnetic properties, biocompability and ease of fabrication. MRI using
+traditional T1- or T2-weighted single mode contrast-enhanced techniques may
+yield inaccurate imaging results. In the present work, a T1/T2 dual mode
+contrast agent based on the super-paramagnetic zinc-manganese ferrite
+(Zn$_{0.3}$Mn$_x$Fe$_{2.7-x}$O$_4$, x= 0, 0.25, 0.75 and 1) NPs with small core
+size and a hydrophilic PEG surface coating is reported. The TEM, TGA and FTIR
+results confirmed the formation of a uniform coating on the NPs surface. The
+MRI analysis revealed that the Zn$_{0.3}$Mn$_{0.5}$Fe$_{2.2}$O$_4$ NPs had the
+maximum image contrast compared to other zinc-manganese ferrite samples. Cell
+viability evaluations revealed that the coated and uncoated particles did not
+inhibit cell growth pattern. The present PEG-coated
+Zn$_{0.3}$Mn$_{0.5}$Fe$_{2.2}$O$_4$ NPs can be utilized as a suitable
+T1/T2-weighted MRI contrast agent for better diagnostic of abnormalities in the
+organs or tissues.",2301.13788v1
+2023-02-06,Observation of Coherently Coupled Cation Spin Dynamics in an Insulating Ferrimagnetic Oxide,"Many technologically useful magnetic oxides are ferrimagnetic insulators,
+which consist of chemically distinct cations. Here, we examine the spin
+dynamics of different magnetic cations in ferrimagnetic NiZnAl-ferrite
+(Ni$_{0.65}$Zn$_{0.35}$Al$_{0.8}$Fe$_{1.2}$O$_4$) under continuous microwave
+excitation. Specifically, we employ time-resolved x-ray ferromagnetic resonance
+to separately probe Fe$^{2+/3+}$ and Ni$^{2+}$ cations on different sublattice
+sites. Our results show that the precessing cation moments retain a rigid,
+collinear configuration to within $\approx$2$^\circ$. Moreover, the effective
+spin relaxation is identical to within $<$10% for all magnetic cations in the
+ferrite. We thus validate the oft-assumed ``ferromagnetic-like'' dynamics in
+resonantly driven ferrimagnetic oxides, where the magnetic moments from
+different cations precess as a coherent, collective magnetization.",2302.03100v1
+2023-10-03,Permanent Magnets Based on Hard Ferrite Ceramics,"Permanent magnets are integral components in many of the modern technologies
+that are critical for the transition to a sustainable society. However, most of
+the high-performance (BHmax > 100 kJ/m3) permanent magnets that are currently
+employed contain rare earth elements (REE), which have long been classified as
+critical materials with a high supply risk and concerns regarding pollution in
+their mining. Therefore, suitable REE-lean/free magnets must be developed in
+order to ensure the sustainability of clean energy generation and electric
+mobility. The REE-free hexagonal ferrites (or hexaferrites) are the most used
+permanent magnets across all applications, with an 85 wt.% pie of the permanent
+magnet market. They are the dominant lower-grade option (BHmax < 25 kJ/m3) due
+to their relatively good hard magnetic properties, high Curie temperature (>700
+K), low cost and good chemical stability. In recent years, the hexaferrites
+have also emerged as candidates for substituting REE-based permanent magnets in
+applications requiring intermediate magnetic performance (25-100 kJ/m3), due to
+considerable performance improvements achieved through chemical tuning,
+nanostructuring and compaction/sintering optimization. This chapter reviews the
+state-of-the-art sintering strategies being investigated with the aim of
+manufacturing hexaferrite magnets with optimized magnetic properties,
+identifying key challenges and highlighting the natural future steps to be
+followed.",2310.02106v1
+2023-10-20,475°C aging embrittlement of partially recrystallized FeCrAl ODS ferritic steels after simulated tube process,"Tube processing and aging effects in FeCrAl ODS steels are investigated in
+four mechanical alloyed ferritic ODS steels, Fe15Cr (SP2), Fe15Cr5Al (SP4),
+Fe15Cr7Al (SP7) and Fe18Cr7Al (SP11). These steels were made into 0.3mm thick
+plates by simulated tube processing (STP). Strengthening after partial
+recrystallization was achieved after the last cold rolling and heat treatment
+step. However, the ductility reduced about one third of the as-extruded steels.
+The STPed steels were aged at 475{\deg}C in sealed vacuum tubes up to 2000 hrs
+and 10000 hrs, respectively. The yield stress and elongation were investigated
+by tensile tests. The results revealed that all the STPed steels fractured in a
+ductile manner irrespective of aging conditions. Aging hardening and ductility
+reduction in STPed steels are similar to as-extruded ones. The STPed ODS steels
+showed similar ageing embrittlement resistance as as-extruded steels, but much
+higher than the non-ODS steels. The aging hardening based on cut-through and
+bow-pass mechanisms were discussed. The time dependent hardening of overaged
+steel (beta prime only) was analyzed as well.",2310.13842v2
+2023-10-24,Complex Poynting vector in gyromagnetic media and its impact on power flow in guided modes,"In this paper, we show the relation between the time-varying spinning nature
+of the instantaneous Poynting vector and the phasor form of the complex
+Poynting vector in the bulk of the gyromagnetic medium. We show the presence of
+a transverse reactive power component in the bulk of the gyrotropic medium,
+even for plane wave propagation. We use a simple quantification technique of
+Poynting vector spin to analyze the rotation of the instantaneous Poynting
+vector using the complex phasor form of the time-averaged Poynting vector. For
+a transverse electric mode, we show the similarity between the Poynting vector
+spin and the photonic spin of the magnetic field. The Poynting vector spin is
+then used to represent the transverse power transfer across a ferrite-air
+interface supporting TE surface wave modes. Considering a gyromagnetic
+ferrite-filled rectangular waveguide following the TE mode profile, we show the
+correspondence between the Poynting vector spin and the overall positive and
+backward power flow. We analytically propose a mechanism to engineer the region
+of the waveguide supporting backward and forward power propagation.",2310.15867v1
+2023-11-03,Effects of Cr content on ion-irradiation hardening of FeCrAl ODS ferritic steels with 9 wt\% Al,"FeCrAl ODS steels for accident tolerant fuel claddings are designed to bear
+high-Cr and Al for enhancing oxidation resistance. In this study, we
+investigated the effects of Cr content on ion-irradiation hardening of three
+ODS ferritic steels with different Cr contents added with 9 wt\% Al, Fe12Cr9Al
+(SP12), Fe15Cr9Al (SP13), and Fe18Cr9Al (SP14). The specimens were irradiated
+with 6.4MeV Fe\textsuperscript{3+} at 300 \textdegree C to nominal 3 dpa. The
+irradiation hardening was measured by nanoindentation method, and the Nix-Gao
+plots were used to evaluate the bulk-equivalent hardness. The results showed
+that the irradiation hardening decreased with increasing Cr content. The reason
+is due to the growth of dislocation loops hindered by solute Cr atoms. TEM
+observations showed both $\langle 100\rangle$ and $1/2\langle 111\rangle$
+dislocation loops existed in the irradiated area. The irradiation hardening was
+estimated by dispersed barrier hardening (DBH) model with dislocation loops.",2311.01879v1
+2023-12-08,Strontium Ferrite Under Pressure: Potential Analogue to Strontium Ruthenate,"Despite the significant attention it has garnered over the last thirty years,
+the paradigmatic material strontium ruthenate remains the focus of critical
+questions regarding strongly correlated materials. As an alternative platform
+to unravel some of its perplexing characteristics, we propose to study the
+isostructural and more correlated material strontium ferrite. Using density
+functional theory combined with dynamical mean-field theory, we attribute the
+experimentally observed insulating behavior at zero pressure to strong local
+electronic correlations generated by Mott and Hund's physics. At high pressure,
+our simulations reproduce the reported insulator-to-metal transition around 18
+GPa. Along with distinctive features of a Hund's metal, the resulting metallic
+state is found to display an electronic structure analogous to that of
+strontium ruthenate, suggesting that it could exhibit similar low-energy
+properties.",2312.05314v1
+2017-03-17,Rotation and Neoclassical Ripple Transport in ITER,"Neoclassical transport in the presence of non-axisymmetric magnetic fields
+causes a toroidal torque known as neoclassical toroidal viscosity (NTV). The
+toroidal symmetry of ITER will be broken by the finite number of toroidal field
+coils and by test blanket modules (TBMs). The addition of ferritic inserts
+(FIs) will decrease the magnitude of the toroidal field ripple. 3D magnetic
+equilibria with toroidal field ripple and ferromagnetic structures are
+calculated for an ITER steady-state scenario using the Variational Moments
+Equilibrium Code (VMEC). Neoclassical transport quantities in the presence of
+these error fields are calculated using the Stellarator Fokker-Planck Iterative
+Neoclassical Conservative Solver (SFINCS). These calculations fully account for
+$E_r$, flux surface shaping, multiple species, magnitude of ripple, and
+collisionality rather than applying approximate analytic NTV formulae. As NTV
+is a complicated nonlinear function of $E_r$, we study its behavior over a
+plausible range of $E_r$. We estimate the toroidal flow, and hence $E_r$, using
+a semi-analytic turbulent intrinsic rotation model and NUBEAM calculations of
+neutral beam torque. The NTV from the $\rvert n \rvert = 18$ ripple dominates
+that from lower $n$ perturbations of the TBMs. With the inclusion of FIs, the
+magnitude of NTV torque is reduced by about 75% near the edge. We present
+comparisons of several models of tangential magnetic drifts, finding
+appreciable differences only for superbanana-plateau transport at small $E_r$.
+We find the scaling of calculated NTV torque with ripple magnitude to indicate
+that ripple-trapping may be a significant mechanism for NTV in ITER. The
+computed NTV torque without ferritic components is comparable in magnitude to
+the NBI and intrinsic turbulent torques and will likely damp rotation, but the
+NTV torque is significantly reduced by the planned ferritic inserts.",1703.06129v2
+2020-01-21,"Mechanical behavior, enhanced dc resistivity, energy band gap and high temperature magnetic properties of Y-substituted Mg-Zn ferrites","We report the synthesis of Y-substituted Mg-Zn ferrites using conventional
+standard ceramic technique. XRD patterns confirm the single phase cubic spinel
+structure up to x = 0.03 and appearance of a secondary phase of YFeO3for higher
+Y contents. FESEM images depict the distribution of grains and EDS spectra
+confirmed the absence of any unwanted element. Completion of solid state
+reaction and formation of spinel structure has been revealed from FTIR spectra.
+The FTIR data along with lattice constant, bulk density and porosity were
+further used to calculate the stiffness constant (Cij), elastic constant and
+Debye temperatures. Mechanical stability of all studied compositions is
+confirmed from Cij using Born stability conditions. Brittleness and isotropic
+nature are also confirmed using Poisson ratio and anisotropy constants,
+respectively. The enhancement of dc electrical resistivity with Y content is
+observed. The energy band gap (increased with Y contents) is found in good
+agreement with dc electrical resistivity. Ferrimagnetic to paramagnetic phase
+change has been observed from the field dependent high temperature
+magnetization curves. The magnetic moments and saturation magnetization were
+found to be decreased with increasing temperature. The Curie temperature (Tc)
+has been measured from temperature dependent magnetic moment (M-T) and initial
+permeability and found to be in good agreement with each other. Decrease in Tc
+with Y content is due to redistribution of cations and weakening of the
+exchange coupling constant. The magnetic phase transition has been analyzed by
+Arrott plot and found to have second order phase transition. The dc resistivity
+endorses the prepared ferrites are suitable for high frequency and high
+temperature magnetic device applications as well.",2001.07313v1
+2020-02-02,A millimeter-wave Bell Test using a ferrite parametric amplifier and a homodyne interferometer,"A combined ferrite parametric amplifier and millimeter-wave homodyne
+interferometer are proposed as an ambient temperature Bell Test. It is shown
+that the non-linear magnetic susceptibility of the yttrium iron garnet (YIG)
+ferrite, on account of its narrow line-width Larmor precessional resonance,
+make it an ideal material for the creation of entangled photons. These can be
+measured using a homodyne interferometer, as the much larger number of
+thermally generated photons associated with ambient temperature emission can be
+screened out. The proposed architecture may enable YIG quantum technology-based
+sensors to be developed, mimicking in the millimeter-wave band the large number
+of quantum optical experiments in the near-infrared and visible regions which
+had been made possible by use of the nonlinear beta barium borate
+ferroelectric, an analogue of YIG. It is illustrated here how the YIG
+parametric amplifier can reproduce quantum optical Type I and Type II wave
+interactions, which can be used to create entangled photons in the
+millimeter-wave band. It is estimated that when half a cubic centimeter of YIG
+crystal is placed in a magnetic field of a few Tesla and pumped with 5 Watts of
+millimeter-wave radiation, approximately 0.5x10^12 entangled millimeter-wave
+photon pairs per second are generated by the spin-wave interaction. This means
+an integration time of only a few tens of seconds is needed for a successful
+Bell Test. A successful demonstration of this will lead to novel architectures
+of entanglement-based quantum technology room temperature sensors,
+re-envisioning YIG as a modern quantum material.",2002.00439v3
+2023-02-21,Per-grain and neighbourhood stress interactions during deformation of a ferritic steel obtained using three-dimensional X-ray diffraction,"Three-dimensional X-ray diffraction (3DXRD) has been used to measure,
+in-situ, the evolution of $\sim 1800$ grains in a single phase low carbon
+ferritic steel sample during uniaxial deformation. The distribution of initial
+residual grain stresses in the material was observed to prevail as plasticity
+builds, though became less pronounced, and therefore less influential as strain
+increased. The initial Schmid factor of a grain was found to be strongly
+correlated to the intergranular stress change and the range of stresses that
+are permissible; a grain well aligned for easy slip is more likely to exhibit a
+range of stresses than those orientated poorly for dislocation motion. The
+orientation path of a grain, however, is not only dependent on its initial
+orientation, but hypothesised to be influenced by its stress state and the
+stress state of its grain environment. A grain neighbourhood effect is
+observed: the Schmid factor of serial adjoining grains influences the stress
+state of a grain of interest, whereas parallel neighbours are much less
+influential. This phenomenon is strongest at low plastic strains only, with the
+effect diminishing as plasticity builds. The influence of initial residual
+stresses becomes less evident, and grains rotate to eliminate any orientation
+dependent load shedding. The ability of the BCC ferrite to exhaust such
+neighbourhood interactions, which would otherwise be detrimental in crystal
+structures with lower symmetric and fewer slip systems, is considered key to
+the high ductility possessed by these materials.",2302.10711v1
+2024-02-15,Site-selective cobalt substitution in La-Co co-substituted magnetoplumbite-type ferrites: $^{59}$Co-NMR and DFT calculation study,"The La-Co co-substituted magnetoplumbite-type (M-type) ferrites
+$A$Fe$_{12}$O$_{19}$ ($A$ = Ca, Sr and Ba, ion sizes Ca$^{2+}$ $<$ Sr$^{2+}$
+$<$ Ba$^{2+}$) with Co compositions around 0.2 have been subjected to
+$^{59}$Co-NMR. The results show that Co occupies the 4f$_1$, 2a and 12k sites,
+and that the smaller the $A$ ion, the more Co tends to occupy the 4f$_1$
+minority spin site, which is effective in enhancing both uniaxial anisotropy
+and magnetisation. First-principles total energy calculations based on density
+functional theory (DFT) of undoped $A$Fe$_{12}$O$_{19}$ and a supercell ($2
+\times 2 \times 1$ of the unit cell) in which 1/96 of Fe$^{3+}$ is replaced by
+Co$^{2+}$ were performed to predict the stable structure and Co occupancy
+sites. The results show that regardless of $A$, Co is most stable when it
+occupies the 4f$_1$ site, followed by the 2a and 12k sites with energy
+differences on the order of 100 meV, and Co practically does not occupy the 2b
+and 4f$_2$ sites. As the $A$ ion becomes smaller, the energy difference when Co
+occupies each Fe site tends to increase, and the Co occupancy of the 4f$_1$
+site also increases. The site selectivity of Co can be roughly explained as a
+result of the difference in uniaxial strain along the $c$-axis associated with
+the difference in $A$. However, the influence of the $A$ ion differs between
+the R and S blocks and the local strain also has a secondary effect on the Co
+distribution. Based on these results, the guidelines for improving the
+performance (anisotropy and magnetisation) of La-Co co-substituted M-type
+ferrite magnets with a limited amount of Co can be summarised as follows: It is
+effective to select as small $A$ ions as possible and to post-anneal at low
+temperature or cool slowly to concentrate Co at the 4f$_1$ site in tetrahedral
+coordination.",2402.09706v1
+2001-08-10,Magnetism and Electronic Structure in ZnFe$_2$O$_4$ and MnFe$_2$O$_4$,"Density functional calculations are used to study magnetic and electronic
+properties of the spinel ferrites, ZnFe$_2$O$_4$ and MnFe$_2$O$_4$. Correct
+magnetic orderings are obtained. ZnFe$_2$O$_4$ is predicted to be a small gap
+insulator in agreement with experiment. MnFe$_2$O$_4$ is found to be a low
+carrier density half-metal in the fully ordered state. However, strong effects
+on the electronic structure are found upon partial interchange of Fe and Mn
+atoms. This indicates that the insulating character may be due to Anderson
+localization associated with the intersite Mn-Fe disorder.",0108176v1
+2001-12-04,Numerical comparison of two approaches for the study of phase transitions in small systems,"We compare two recently proposed methods for the characterization of phase
+transitions in small systems. The validity and usefulness of these approaches
+are studied for the case of the q=4 and q=5 Potts model, i.e. systems where a
+thermodynamic limit and exact results exist. Guided by this analysis we discuss
+then the helix-coil transition in polyalanine, an example of structural
+transitions in biological molecules.",0112050v1
+2002-05-02,Current and vortex statistics in microwave billiards,"Using the one-to-one correspondence between the Poynting vector in a
+microwave billiard and the probability current density in the corresponding
+quantum system probability densities and currents were studied in a microwave
+billiard with a ferrite insert as well as in an open billiard. Distribution
+functions were obtained for probability densities, currents and vorticities. In
+addition the vortex pair correlation function could be extracted. For all
+studied quantities a complete agreement with the predictions from the
+random-superposition-of-plane-waves approach was obtained.",0205042v1
+2006-06-25,Inductive Detection of Magnetostrictive Resonance,"We have developed an inductive method to detect the magnetostrictive
+resonance signal and applied it to an ultrasonic magnetostrictive transducer
+sample. Slab shaped ferrite samples are mounted in an RF coil and actuated by
+pulse modulated RF magnetic field. A DC magnetic field is also applied and the
+resonance signal from the sample is detected by the same coil after the RF
+field is turned off. The detector system is similar to a conventional pulse NMR
+system with quadrature detection. The detected signal is sensitive to the bias
+DC field strength and direction as well as the dimension of the sample.",0606636v1
+2005-01-06,Booster High-level RF Frequency Tracking Improvement Via Bias-Curve Optimization,"It is important to improve the frequency tracking between the RF drive and
+the cavity field for the purpose of reducing longitudinal phase oscillations
+and increasing the effective accelerating voltage. And this is especially
+beneficial for Booster running at higher intensity with smaller beam emittance.
+Optimizing the bias supply current curve for the ferrite tuners can reduce the
+phase error between the RF drive and the cavity field, and also improve the
+HLRF-to-LLRF frequency tracking efficiency.",0501028v1
+2005-01-14,Unidirectional Magnetostatic Waves,"Dispersion characteristics of magnetostatic waves in tangentially magnetized
+to saturation ferrite film with a ""magnetic wall"" condition (tangential
+component of microwave magnetic field is equal to zero) on the one of the film
+surface were calculated. It is found, that unidirectional magnetostatic waves
+appear in this geometry: they can transfer energy only in one direction and
+fundamentally cannot transfer energy in an opposite direction.",0501074v2
+2003-05-12,Comment on Repulsive Casimir Forces,"A recent theoretical calculation shows that the Casimir force between two
+parallel plates can be repulsive for plates with nontrivial magnetic properties
+(O. Kenneth et al., Phys. Rev. Lett. 89, 033001 (2002)). According to the
+authors, the effect may be observed with known materials, such as ferrites and
+garnets, and it might be possible to engineer micro- or nanoelectromechanical
+systems (MEMS or NEMS) that could take advantage of a short range repulsive
+force. Here we show that on the contrary the Casimir force between two parallel
+plates in vacuum at micron and submicron distance is always attractive.",0305065v1
+2007-11-29,Realization of XNOR and NAND spin-wave logic gates,"We demonstrate the functionality of spin-wave logic XNOR and NAND gates based
+on a Mach-Zehnder type interferometer which has arms implemented as sections of
+ferrite film spin-wave waveguides. Logical input signals are applied to the
+gates by varying either the phase or the amplitude of the spin waves in the
+interferometer arms. This phase or amplitude variation is produced by Oersted
+fields of dc current pulses through conductors placed on the surface of the
+magnetic films.",0711.4720v1
+2008-02-20,Electric-field-induced spin-flop in BiFeO3 single crystals at room-temperature,"Bismuth ferrite, BiFeO3, is the only known room-temperature 'multiferroic'
+material. We demonstrate here, using neutron scattering measurements in high
+quality single crystals, that the antiferromagnetic and ferroelectric orders
+are intimately coupled. Initially in a single ferroelectric state, our crystals
+have a canted antiferromagnetic structure describing a unique cycloid. Under
+electrical poling, polarisation re-orientation induces a spin flop. We argue
+here that the coupling between the two orders may be stronger in the bulk than
+that observed in thin films where the cycloid is absent.",0802.2915v1
+2008-04-21,Unusual magnetic behavior in ferrite hollow nanospheres,"We report unusual magnetic behavior in iron oxide hollow nanospheres of 9.3
+$nm$ in diameter. The large fraction of atoms existing at the inner and outer
+surfaces gives rise to a high magnetic disorder. The overall magnetic behavior
+can be explained considering the coexistence of a soft superparamagnetic phase
+and a hard phase corresponding to the highly frustrated cluster-glass like
+phase at the surface regions.",0804.3292v1
+2008-04-25,Long-range antiferromagnetic interactions in ZnFe2O4 and CdFe2O4,"For the first time, the Fe-Fe interactions in the geometrically frustrated
+antiferromagnetic systems of zinc and cadmium ferrites are determined
+quantitatively by the first-principles methods of density functional theory.
+Both the generalized gradient approximation (GGA) as well as GGA plus the
+onesite Coulomb interaction (GGA+U) are considered for the exchange-correlation
+energy functional. The interactions up to third neighbours are found to be all
+antiferromagnetic for both materials, regardless of which approximation scheme
+(GGA or GGA+U) is used. Surprisingly, the thirdneighbour interactions are
+estimated to be much stronger than the second-neighbour interactions and on the
+same order in magnitude as the first-neighbour interactions.",0804.4059v2
+2008-05-07,Design Methodology and Manufacture of a Microinductor,"Potential core materials to supersede ferrite in the 0.5-10 MHz frequency
+range are investigated. The performance of electrodeposited nickel-iron,
+cobalt-iron-copper alloys and the commercial alloy Vitrovac 6025 have been
+assessed through their inclusion within a custom-made solenoid microinductor.
+Although the present inductor, at 500 KHz, achieves 77% power efficiency for
+24.7W/cm3 power density, an optimized process predicts a power efficiency of
+97% for 30.83W/cm3 power density. The principle issues regarding microinductor
+design and performance are discussed.",0805.0859v1
+2008-11-14,Almeida-Thouless Line in BiFeO3: Is Bismuth Ferrite a mean field spin glass?,"Low-temperature magnetic properties of epitaxial BiFeO3 thin films grown on
+(111)-SrTiO3 substrates have been studied. ZFC and FC magnetization curves show
+a large discrepency beginning at a characteristic temperature Tf that is
+dependent on the magnetic-field strengh. Tf(H) varies according to the well
+known de Aleimda-Thouless line (varies in Hexp(2/3)) suggesting an acentric
+long rnage spin-glass behavior and mean field system.",0811.2347v1
+2008-11-21,Frequency-dependent reflection of spin waves from a magnetic inhomogeneity induced by a surface DC-current,"The reflectivity of a highly localized magnetic inhomogeneity is
+experimentally studied. The inhomogeneity is created by a dc-current carrying
+wire placed on the surface of a ferrite film. The reflection of propagating
+dipole-dominated spin-wave pulses is found to be strongly dependent on the
+spin-wave frequency if the current locally increases the magnetic field. In the
+opposite case the frequency dependence is negligible.",0811.3491v1
+2009-01-18,Generation of pulse trains by current-controlled magnetic mirrors,"The evolution of a spin-wave packet trapped between two direct
+current-carrying wires placed on the surface of a ferrite film is observed by
+Brillouin light scattering. The wires act as semi-transparent mirrors confining
+the packet. Because the spin-wave energy partially passes through these
+mirrors, trains of spin-wave packets are generated outside the trap. A
+numerical model of this process is presented and applied to the case when the
+current in the wires is dynamically controlled. This dynamical control of the
+mirror reflectivity provides new functionalities interesting for the field of
+spin-wave logic like that of a spin-wave memory cell.",0901.2704v1
+2009-01-20,Phase sensitive Brillouin scattering measurements with a novel magneto-optic modulator,"A recently reported phase sensitive Brillouin light scattering technique is
+improved by use of a magnetic modulator. This modulator is based on Brillouin
+light scattering in a thin ferrite film. Using this magnetic modulator in time-
+and space Brillouin light scattering measurements we have increased phase
+contrast and excluded influence of optical inhomogeneities in the sample. We
+also demonstrate that the quality of the resulting interference patterns can be
+improved by data postprocessing using the simultaneously recorded information
+about the reference light.",0901.3031v1
+2009-02-09,Induced Violation of Time-Reversal Invariance in the Regime of Weakly Overlapping Resonances,"We measure the complex scattering amplitudes of a flat microwave cavity (a
+""chaotic billiard""). Time-reversal T-invariance is partially broken by a
+magnetized ferrite placed within the cavity. We extend the random-matrix
+approach to T-violation in scattering, fit some of the properties of the
+scattering amplitudes, and then successfully predict others. Our work
+constitutes the most precise test of the theoretical approach to T-violation
+within the framework of random-matrix theory so far available.",0902.1418v2
+2009-06-26,Relaxation Mechanism for Ordered Magnetic Materials,"We have formulated a relaxation mechanism for ferrites and ferromagnetic
+metals whereby the coupling between the magnetic motion and lattice is based
+purely on continuum arguments concerning magnetostriction. This theoretical
+approach contrasts with previous mechanisms based on microscopic formulations
+of spin-phonon interactions employing a discrete lattice. Our model explains
+for the first time the scaling of the intrinsic FMR linewidth with frequency,
+and 1/M temperature dependence and the anisotropic nature of magnetic
+relaxation in ordered magnetic materials, where M is the magnetization. Without
+introducing adjustable parameters our model is in reasonable quantitative
+agreement with experimental measurements of the intrinsic magnetic resonance
+linewidths of important class of ordered magnetic materials, insulator or
+metals.",0906.4979v1
+2009-07-17,"""Rectifying"" reflection from a magnetic photonic crystal","When an oscillating line source is placed in front of a special mirror
+consisting of an array of flat uniformly spaced ferrite rods, half of the image
+disappeared at some frequency. We believe that this comes from the coupling to
+photonic states of the magnetic surface plasmon band. These states exhibit
+giant circulations that only go in one direction due to time reversal symmetry
+breaking. Possible applications of this ""rectifying"" reflection include a
+robust one-way waveguide, a 90 degree beam bender and a beam splitter, which
+are shown to work even in the deep subwavelength scale.",0907.3127v1
+2010-01-03,Electrically stabilized magnetic vortex and antivortex states in magnetic dielectrics,"The micromagnetic distribution in a dielectric nanoparticle is theoretically
+considered. It is shown that the existence of inhomogeneous magnetoelectric
+interaction in magnetic dielectrics provides the possibility to stabilize the
+vortex and antivortex state. The estimation of the critical voltage necessary
+for vortex/antivortex nucleation in bismuth ferrite and iron garnet
+nanoparticles yields a value of +/-150 V. This system can be considered as
+electrically switchable two state-logic magnetic element.",1001.0391v4
+2011-03-18,Are magnetite (Fe3O4) films on MgAl2O4 auxetic?,"Magnetite (Fe3O4) films were fabricated on MgAl2O4 (001) single crystal
+substrates by pulsed laser deposition. In-plane and out-of-plane lattice
+constants were determined by X-ray diffraction. The apparent Poisson's ratio
+was determined as the negative ratio of the out-of-plane to in-plane strains.
+The results show that (i) the determination of Poisson's ratio by this method
+is only reliable for fully strained films and (ii) Poisson's ratio = 0.3 along
+the <100> direction is positive for this archetypal ferrite. Fe3O4 films grown
+on MgAl2O4 (001) are not auxetic.",1103.3666v1
+2011-09-09,Modélisation multidomaine du comportement magnéto-mécanique des aciers dual-phases,"The microstructure and mechanical behavior of dual-phase steels are highly
+sensitive to the variation of the process (heat treatments). Online control by
+magnetic method is relevant. A measurement under applied stress must be
+considered. The dual-phase is a two-phase medium (ferrite / martensite). Each
+phase can be considered as a sphere embedded in a homogeneous equivalent
+medium. The model used for each phase is based on a magneto-mechanical coupled
+model. This is an explicit single crystalline model representative of the
+behavior of the corresponding phase. Localization rules allow the simulation of
+the two-phases medium. Experiments and modeling are compared.",1109.1915v1
+2011-10-10,Coaxial Wire Measurements of Ferrite Kicker Magnets,"Fast kicker magnets are used to inject beam into and eject beam out of the
+CERN accelerator rings. These kickers are generally transmission line type
+magnets with a rectangular shaped aperture through which the beam passes.
+Unless special precautions are taken the impedance of the yoke can provoke
+significant beam induced heating, especially for high intensities. In addition
+the impedance may contribute to beam instabilities. The results of longitudinal
+and transverse impedance measurements, for various kicker magnets, are
+presented and compared with analytical calculations: in addition predictions
+from a numerical analysis are discussed.",1110.2024v1
+2012-02-28,An original unified approach for the description of phase tranformations in steel during cooling : first application to binary Fe-C,"Exploiting Landau's theory of phase transformations, defining an original
+order parameter and using the phenomenological transformation temperatures, it
+is reported that it is possible to describe in a global approach the conditions
+for the formation of each phase (ferrite, bainite, martensite) from austenite
+during cooling in steel. It allowed to propose a new rigorous classification of
+the different thermodynamic conditions controlling each phase tranformation. In
+a second step, the approach predicts naturally the effect of cooling rate on
+the bainite start temperature. Finally perspectives are assessed to extend the
+approach in order to take into account the effect of an external field such as
+applied stress.",1202.6194v2
+2012-07-04,Phenomenological theory of spin-orbit phase transitions,"This work is devoted to the logical proof of the Goodenough and Khomskii idea
+of the existence of spin-orbit transitions in transition magnetic crystals. In
+agreement with the basics of the Landau theory of phase transitions the
+phenomenological theory of spin-orbit transitions is constructed. The general
+scheme of the theory is illustrated by the application to the description of
+magnetic and structural transformations in the copper ferrite CuFe2O4.",1207.0899v1
+2012-08-10,Resonant features of planar Faraday metamaterial with high structural symmetry,"The transmission of electromagnetic wave through the planar chiral structure,
+loaded with the gyrotropic medium on the longitudinal magnetic field is
+studied. The frequency dependence of the metamaterial resonance and the angle
+of rotation of the polarization plane are obtained. We define both
+theoretically and experimentally the range of frequencies and magnetic fields,
+where the angle of polarization plane rotation for the metamaterial is
+essentially higher than for a single ferrite slab.",1208.2195v2
+2013-10-24,Electronic structure and optical band gap determination of NiFe2O4,"In a theoretical study we investigate the electronic structure and the band
+gap of the inverse spinel ferrite NiFe2O4. The experimental optical absorption
+spectrum is accurately reproduced by fitting the Tran-Blaha parameter in the
+modified Becke-Johnson potential. The accuracy of the commonly applied Tauc
+plot to find the optical gap is assessed based on the computed spectra and we
+find that this approach can lead to a misinterpretation of the experimental
+data. The minimum gap of NiFe2O4 is found to be a 1.53eV wide indirect gap,
+which is located in the minority spin channel.",1310.6667v1
+2013-12-12,Physical and Structural Design of Fast Extraction Kickers for CSNS/RCS,"China Spallation Neutron Source (CSNS) is a high intensity beam facility
+being built now in China. Three kicker assemblies, eight pulsed magnets, will
+be used in the CSNS rapid circle synchrotron (RCS). The physical and structural
+designs of eight kicker magnets that are grouped in 5 different types are
+presented. The results of OPERA-3D simulation show that magnet center field
+integral meet the physics requirements of design by choosing a suitable magnet
+coil structure. Field uniformity for 60% width is +/-0.7%. The ferrite magnet
+structure and composition is introduced, and the high voltage feedthrough
+design, the installation of six magnets in long vacuum cavity design is
+discussed.",1312.3407v1
+2014-01-29,Bimodal island size distribution in heteroepitaxial growth,"A bimodal size distribution of two dimensional islands is inferred during
+interface formation in heteroepitaxial growth of Bismuth Ferrite on (001)
+oriented SrTiO3 by sputter deposition. Features observed by in-situ x-ray
+scattering are explained by a model where coalescence of islands determines the
+growth kinetics with negligible surface diffusion on SrTiO3. Small clusters
+maintain a compact shape as they coalesce, while clusters beyond a critical
+size impinge to form large irregular connected islands and a population of
+smaller clusters forms in the spaces between the larger ones.",1401.7643v1
+2014-04-10,Design and performance of LLRF system for CSNS/RCS,"The rapid cycling synchrotron (RCS) is part of China Spallation Neutron
+Source (CSNS). The RCS provides 1.6GeV protons with a repetition rate of 25Hz.
+The RF system in RCS is mainly composed of a ferrite loaded RF cavity, a high
+power tetrode amplifier, a bias supply of 3300A and a digital low level RF
+(LLRF) system based on FPGA. The major challenge of the LLRF system is to solve
+problems caused by rapid frequency sweeping and heavy beam loading effect. This
+paper will present the design and structure of the LLRF system, and show
+results of performance tests.",1404.2658v1
+2015-02-04,Instability of a ferrimagnetic state of a frustrated S=1/2 Heisenberg antiferromagnet in two dimensions,"To clarify the instability of the ferrimagnetism which is the fundamental
+magnetism of ferrite, numerical-diagonalization study is carried out for the
+two-dimensional S=1/2 Heisenberg antiferromagnet with frustration. We find that
+the ferrimagnetic ground state has the spontaneous magnetization in small
+frustration; due to a frustrating interaction above a specific strength, the
+spontaneous magnetization discontinuously vanishes so that the ferrimagnetic
+state appears only under some magnetic fields. We also find that, when the
+interaction is increased further, the ferrimagnetism disappears even under
+magnetic field.",1502.01071v1
+2015-05-05,Asymmetric Band Diagrams in Photonic Crystals with a Spontaneous Nonreciprocal Response,"We study the propagation of electromagnetic waves in layered photonic
+crystals formed by materials with a spontaneous nonreciprocal response, such as
+Tellegen (axion) media or topological insulators. Surprisingly, it is proven
+that stratified Tellegen photonic crystals that break simultaneously the space
+inversion and time reversal symmetries have always symmetric dispersion
+diagrams. Interestingly, we show that by combining chiral and nonreciprocal
+materials the photonic band diagrams can exhibit a spectral asymmetry such that
+. Furthermore, it is demonstrated that in some conditions two juxtaposed
+Tellegen medium layers have an electromagnetic response analogous to that of a
+biased ferrite slab.",1505.01200v1
+2015-10-24,Graphene Transverse Electric Surface Plasmon Detection using Nonreciprocity Modal Discrimination,"We present a magnetically biased graphene-ferrite structure discriminating
+the TE and TM plasmonic modes of graphene. In this structure, the graphene TM
+plasmons interact reciprocally with the structure. In contrast, the graphene TE
+plasmons exhibit nonreciprocity. This nonreciprocity is manifested in
+unidirectional TE propagation in a frequency band close to the interband
+threshold frequency. The proposed structure provides a unique platform for the
+experimental demonstration of the unusual existence of the TE plasmonic mode in
+graphene.",1510.07164v2
+2016-06-02,Circulator based on spoof surface plasmon polaritons,"Circulators based on spoof surface plasmon polaritons are designed and
+analyzed. In the letter, we use blade structure to realize the propagation of
+SSPPs wave and a matching transition is used to feed energy from coplanar
+waveguide to the SSPPs. And the circulator shows good nonreciprocal
+transmission characteristics. The simulation results indicate that in the
+frequency band from 5 to 6.6 GHz, the isolation degree and return loss
+basically reaches 15dB and the insertion loss is less than 0.5dB. Moreover, the
+use of confinement electromagnetic waves can decrease the size of the ferrite
+and show a broadband characteristic.",1606.00567v1
+2018-11-19,Photovoltaic effect in multi-domain ferroelectric perovskite oxides,"We propose a device model that elucidates the role of domain walls in the
+photovoltaic effect in multi-domain ferroelectric perovskites. The model
+accounts for the intricate interplay between ferroelectric polarization, space
+charges, photo-generation and electronic transport. When applied to bismuth
+ferrite, results show a significant electric potential step across both
+71-degree and 109-degree domain walls, which in turn contributes to the
+photovoltaic (PV) effect. We also find a strong correlation between
+polarization and oxygen octahedra tilts, which indicates the nontrivial role of
+the latter in the PV effect. The domain wall-based PV effect is further shown
+to be additive in nature, allowing for the possibility of generating
+above-bandgap voltage",1811.07948v1
+2019-05-24,Photovoltage from ferroelectric domain walls in BiFeO$_3$,"We calculate the component of the photovoltage in bismuth ferrite that is
+generated by ferroelectric domain walls, using first-principles methods, in
+order to compare its magnitude to the experimentally measured photovoltage. We
+find that excitons at the ferroelectric domain walls form an electric dipole
+layer resulting in a domain-wall driven photovoltage. This is of the same order
+of magnitude as the experimentally measured one, but only if the carrier
+lifetimes and diffusion lengths are larger than previously assumed.",1905.10321v2
+2019-05-28,"Determination of the magnetic permeability, electrical conductivity, and thickness of ferrite metallic plates using a multi-frequency electromagnetic sensing system","In this paper, an inverse method was developed which can, in principle,
+reconstruct arbitrary permeability, conductivity, thickness, and lift-off with
+a multi-frequency electromagnetic sensor from inductance spectroscopic
+measurements. The system fives the error of ""Bad character(s) in field
+Abstract"" for no reason. Please refer to manuscript for the full abstract.",1905.13081v1
+2010-05-21,A model of homogeneous semicoherent interphase boundary for heterophase precipitates in substitution alloys under irradiation,"The model of homogeneous semicoherent interphase boundary describes the
+processes of absorption and thermoactivated migration of irradiation-produced
+inequilibrium point defects at a semicoherent boundary between a heterophase
+precipitate and a substitution solid solution. Within this model the kinetics
+of evolution of the sizes of precipitates of constant chemical composition
+under irradiation is investigated. The results obtained are compared to the
+experimental data [I. Monnet et al., J. Nucl. Mater. 335 (2004) 311] for the
+ferritic ODS steel EM10+MgO under electron irradiation.",1005.3995v1
+2012-01-08,Effect of mechanical stresses on the coercive force of the heterophase non-interacting nanoparticles,"The theoretical analysis of the effect of uniaxial stress on the
+magnetization of the system of noninteracting nanoparticles is done by an
+example of heterophase particles of maghemite, epitaxially coated with cobalt
+ferrite. It is shown that stretching leads to a decrease in the coercive force
+$H_c$, and compression leads to its growth. The residual saturation
+magnetization $I_{rs}$ of nanoparticles does not change. With increasing of
+interfacial exchange interaction, coercive force varies nonmonotonically",1201.1629v1
+2012-04-24,"Magnetostatic Spin Waves and Magnetic-Wave Chaos in Ferromagnetic Films. III. Numeric Simulations of Microwave-Band Magnetic Chaos, Its Synchronization and Application to Secure Communication","Selected results of original numeric simulations of non-linear magnetostatic
+spin waves and microwave-frequency magnetic chaos in ferrite films are
+expounded, as third part of the work whose first two parts are recent arXive
+preprints 1204.0200 and 1204.2423 . Especially we consider crucial role of
+parametric processes in creating the chaos and simultaneously obstacles to its
+synchronization, and examine some possibilities of good enough synchronization
+(to an extent allowing its use for direct secure communication in microwave
+band).",1204.5410v1
+2013-09-28,High-efficiency GHz frequency doubling without power threshold in thin-film Ni81Fe19,"We demonstrate efficient second-harmonic generation at moderate input power
+for thin film Ni81Fe19 undergoing ferromagnetic resonance (FMR). Powers of the
+generated second-harmonic are shown to be quadratic in input power, with an
+upconversion ratio three orders of magnitude higher than that demonstrated in
+ferrite. The second harmonic signal generated exhibits a significantly lower
+linewidth than that predicted by low-power Gilbert damping, and is excited
+without threshold. Results are in good agreement with an analytic, approximate
+expansion of the Landau-Lifshitz-Gilbert (LLG) equation.",1309.7483v1
+2013-09-18,Observation of plastoferrite character and semiconductor to metal transition in soft ferromagnetic Li0.5Mn0.5Fe2O4ferrite,"We prepared Li0.5Mn0.5Fe2O4 ferrite through chemical reaction in highly
+acidic solution and subsequent sintering of chemical routed powder at
+temperatures > 800 0C. Surface morphology showed plastoferrite character for
+sintering temperature > 1000 0C. Mechanical softening of metal-oxygen bonds at
+higher measurement temperatures stimulated delocalization of charge carriers,
+which were strongly localized in A and B sites of the spinel structure at lower
+temperatures. The charge delocalization process has activated semiconductor to
+metallic transition in ac conductivity curves, obeyed by Jonscher power law and
+Drude equation, respectively. Metallic state is also confirmed by the frequency
+dependence of dielectric constant curves.",1309.7956v1
+2020-12-06,Magnetless Circulators Based on Synthetic Angular-Momentum Bias: Recent Advances and Applications,"In this paper, we discuss recent progress in magnet-free non-reciprocal
+structures based on a synthetic form of angular momentum bias imparted via
+spatiotemporal modulation. We discuss how such components can support metrics
+of performance comparable with traditional magnetic-biased ferrite devices,
+while at the same time offering distinct advantages in terms of reduced size,
+weight, and cost due to the elimination of magnetic bias. We further provide an
+outlook on potential applications and future directions based on these
+components, ranging from wireless full-duplex communications to metasurfaces
+and topological insulators.",2012.03164v1
+2012-05-16,Magnetic properties of BiFeO3 micro-cubes synthesized by microwave agitation,"In this report we present results of magnetization measurements and
+investigation of aging and memory effect in bismuth ferrite multiferroic
+micro-cubes obtained by means of simple microwave synthesis procedure. It is
+found that difference between FC and ZFC magnetizations appears at the
+temperature of freezing of ferromagnetic domain walls. The decay of the
+magnetic moment vs. time described by power-law relation and the absence of
+memory effect indicate domain growth mechanism rather than the spin-glass
+phase.",1205.3653v1
+2020-05-21,Cluster Dynamics Modeling of Niobium and Titanium Carbide Precipitates,"Kinetics of niobium and titanium carbide precipitates in iron has been
+simulated with cluster dynamics. The simulations, carried out in austenite and
+ferrite for niobium carbides, respectively in austenite for titanium carbide,
+were analyzed for dependency on temperature, solute concentration, and initial
+cluster distribution. The results are presented for different temperatures and
+solute concentrations and compared to available experimental data. They show
+little impact of initial cluster distribution beyond a certain relaxation time
+and that highly dilute alloys with only monomers present a significantly
+different behavior than less dilute alloys or alloys with different initial
+cluster distribution.",2005.10574v2
+2020-08-31,Power Module (PM) core-specific parameters for a detailed design-oriented inductor model,"This paper obtains shape related parameters and functions of a Power Module
+ferrite core which can be required in a design-oriented inductor model, which
+is a fundamental tool to design any electronic power converter and its control
+policy. Some particular modifications have been introduced into the
+standardized method of obtaining characteristics core areas and lengths. Also,
+a novel approach is taken to obtain the air gap reluctance as a function of air
+gap length for that specific core shape.",2008.13659v3
+2020-10-02,Effect of tensile stresses on bainitic isothermal transformation,"The effects of tensile stresses on isothermal bainitic transformation were
+studied in the case of a 35MV7 steel. The modification of transformation
+kinetics and the presence of transformation plasticity is shown in a first
+step. Furthermore the effect of stress on the morphological modifications of
+the ferrite laths is illustrated. The role of the stress on these changes is
+analysed.",2010.00856v1
+2021-06-01,Energetic particle transport in optimized stellarators,"Nine stellarator configurations, three quasiaxisymmetric, three
+quasihelically symmetric and three non-quasisymmetric are scaled to ARIES-CS
+size and analyzed for energetic particle content. The best performing
+configurations with regard to energetic particle confinement also perform the
+best on the neoclassical {\Gamma}c metric, which attempts to align contours of
+the second adiabatic invariant with flux surfaces. Quasisymmetric
+configurations that simultaneously perform well on {\Gamma}c and quasisymmetry
+have the best overall confinement, with collisional losses under 3%,
+approaching the performance of ITER with ferritic inserts.",2106.00716v1
+2022-12-19,Steel Phase Kinetics Modeling using Symbolic Regression,"We describe an approach for empirical modeling of steel phase kinetics based
+on symbolic regression and genetic programming. The algorithm takes processed
+data gathered from dilatometer measurements and produces a system of
+differential equations that models the phase kinetics. Our initial results
+demonstrate that the proposed approach allows to identify compact differential
+equations that fit the data. The model predicts ferrite, pearlite and bainite
+formation for a single steel type. Martensite is not yet included in the model.
+Future work shall incorporate martensite and generalize to multiple steel types
+with different chemical compositions.",2212.10284v1
+2003-05-13,Thermal Remagnetization in Polycrystalline Permanent Magnets,"The thermal remagnetization (TR), i.e. the reentrance of magnetization upon
+heating in a steady-field demagnetized sample, is a common feature to the four
+types of polycrystalline permanent magnets, mainly utilized for practical
+purposes, i.e. barium ferrites, SmCo5, Sm2Co17 and NdFeB magnets. The effect is
+small for pinning controlled and large for nucleation controlled magnets. The
+effect is strongly dependent on the demagnetization factor and may reach nearly
+100 per cent in SmCo5 samples measured in a closed circuit. The TR is very
+sensitive to a small superimposed steady field. The maximum effect and the
+position of the peak is dependent on the initial temperature. The direction of
+the TR is correlated with the temperature coefficient of the coercivity,
+resulting in a inverse TR in barium ferrite. The susceptibility of the
+thermally remagnetized samples is increased. Repeated cycles of steady-field
+demagnetization followed by heating result in the same TR. The phenomenology of
+TR and ITR is explained by means of a model taking into account both the
+internal field fluctuations due to grain interactions and the decay of single
+domain grains into multi-domain state. By taking the measured temperature
+dependencies of the coercivity and the saturation magnetization the theory is
+able to reproduce the experiments very well, allowing to determine the width of
+the field fluctuations, the width of the switching field distribution and an
+internal demagnetization factor as characteristics of the materials by fitting.",0305292v1
+2005-08-31,Spinel ferrites: old materials bring new opportunities for spintronics,"Over the past few years, intensive studies of ultrathin epitaxial films of
+perovskite oxides have often revealed exciting properties like giant
+magnetoresistive tunnelling and electric field effects. Spinel oxides appear as
+even more versatile due to their more complex structure and the resulting many
+degrees of freedom. Here we show that the epitaxial growth of nanometric
+NiFe2O4 films onto perovskite substrates allows the stabilization of novel
+ferrite phases with properties dramatically differing from bulk ones. Indeed,
+NiFe2O4 films few nanometres thick have a saturation magnetization at least
+twice that of the bulk compound and their resistivity can be tuned by orders of
+magnitude, depending on the growth conditions. By integrating such thin NiFe2O4
+layers into spin-dependent tunnelling heterostructures, we demonstrate that
+this versatile material can be useful for spintronics, either as a conductive
+electrode in magnetic tunnel junctions or as a spin-filtering insulating
+barrier in the little explored type of tunnel junction called spin-filter. Our
+findings are thus opening the way for the realisation of monolithic spintronics
+architectures integrating several layers of a single material, where the layers
+are functionalised in a controlled manner.",0508764v1
+2009-06-16,Microwave Technologies-- Determination of Magnetic and Dielectric Materials Microwave Properties,"In this study, four different techniques are presented. 1 Rectangular
+waveguide measurement technique for normal microwave materials microwave
+properties such as permeability and permittivity. This technique removed guess
+parameter and dispersive effect issues of the old waveguide measurement
+techniques. It projects a new route for determination of any microwave
+materials magnetic and dielectric properties without using any guesses. 2
+Coaxial probe measurement technique for the liquid and biological tissues
+dielectric permittivity. This coaxial probe technique has an advantage which is
+to attain the highest reflected signal from the coaxial probe tip, so that it
+is a fast and very sensitive technique to differentiate lossy materials
+dielectric permittivity. This technique could be useful non destructive
+detections for tumors in hospital and non destructive detections for chemical
+liquids as well. 3 A microstripline measurement technique for oxides microwave
+measurement at low frequency spectra where the waveguide technique becomes
+robot and cumbersome. 4 A new methodology is presented for the rectangular
+waveguide technique to determine microwave metamaterials refractive index,
+permeability and permittivity using the rectangular waveguide. In summary, the
+presented techniques are capable enough to determine magnetic and non magnetic
+solid state materials, liquids, powders and biological tissues microwave
+properties from the broad microwave frequencies spectra between 1 GHz to 50
+GHz. Lastly, a special ferrites microwave properties are also presented since
+the negative refractive index from the insulator ferrite could be an
+interesting subject.",0906.2928v1
+2009-10-30,Resonant x-ray scattering in 3d-transition-metal oxides: Anisotropy and charge orderings,"The structural, magnetic and electronic properties of transition metal oxides
+reflect in atomic charge, spin and orbital degrees of freedom. Resonant x-ray
+scattering (RXS) allows us to perform an accurate investigation of all these
+electronic degrees. RXS combines high-Q resolution x-ray diffraction with the
+properties of the resonance providing information similar to that obtained by
+atomic spectroscopy (element selectivity and a large enhancement of scattering
+amplitude for this particular element and sensitivity to the symmetry of the
+electronic levels through the multipole electric transitions). Since electronic
+states are coupled to the local symmetry, RXS reveals the occurrence of
+symmetry breaking effects such as lattice distortions, onset of electronic
+orbital ordering or ordering of electronic charge distributions. We shall
+discuss the strength of RXS at the K absorption edge of 3d transition-metal
+oxides by describing various applications in the observation of local
+anisotropy and charge disproportionation. Examples of these resonant effects
+are (I) charge ordering transitions in manganites, Fe3O4 and ferrites and (II)
+forbidden reflections and anisotropy in Mn3+ perovskites, spinel ferrites and
+cobalt oxides. In all the studied cases, the electronic (charge and/or
+anisotropy) orderings are determined by the structural distortions.",0910.5789v1
+2010-09-17,Investigation of multiple echo signals formation mechanism in magnet at excitation by two arbitrary radio-frequency pulses,"The quantum-mechanical calculations of intensities and time moments of
+appearance of multiple spin echo signals of excitation of nuclear spin system
+of magnet by two arbitrary width radio-frequency pulses were carried out. This
+method was used by us earlier at consideration of multiple-pulse analogs of
+single-pulse echo in multidomain magnets upon sudden jumps of the effecting
+magnetic field in the rotating coordinate system during the action of
+radio-frequency pulse. The formation mechanisms of echo signals are discussed.
+The appearance of four primary stimulated echo signals is predicted. The total
+number of echo signals at fixed parameters of radio-frequency pulses does not
+exceed thirteen ones. Theoretical conclusions are in compliance with
+experiments carried out on lithium ferrite. As it was established by us earlier
+in this magnetic dielectric, in difference from ferrometals, it is observed
+very short relaxation times of single-pulse and two-pulse stimulated echoes,
+and the contribution of radio-frequency pulse fronts distribution mechanism is
+insignificant. For this reason lithium ferrite is a good material for the
+experimental verification of theoretical conclusions in experimental conditions
+most close to the theoretical model.",1009.3371v1
+2011-03-25,"Electronic Structures, Born Effective Charges and Spontaneous Polarization in Magnetoelectric Gallium Ferrite","We present a theoretical study of the structure-property correlation in
+gallium ferrite, based on the first principles calculations followed by a
+subsequent comparison with the experiments. Local spin density approximation
+(LSDA+U) of the density functional theory has been used to calculate the ground
+state structure, electronic band structure, density of states and Born
+effective charges. Calculations reveal that the ground state structure is
+orthorhombic Pc21n having A-type antiferromagnetic spin configuration, with
+lattice parameters matching well with those obtained experimentally. Plots of
+partial density of states of constituent ions exhibit noticeable hybridization
+of Fe 3d, Ga 4s, Ga 4p and O 2p states. However, the calculated charge density
+and electron localization function show largely ionic character of the Ga/Fe-O
+bonds which is also supported by lack of any significant anomaly in the
+calculated Born effective charges with respect to the corresponding nominal
+ionic charges. The calculations show a spontaneous polarization of ~ 59
+microC/cm^2 along b-axis which is largely due to asymmetrically placed Ga1,
+Fe1, O1, O2 and O6 ions.",1103.4935v2
+2011-10-21,Exchange-spring behavior in bimagnetic CoFe2O4/CoFe2 nanocomposite,"In this work we report a study of the magnetic behavior of ferrimagnetic
+oxide CoFe2O4 and ferrimagnetic oxide/ferromagnetic metal CoFe2O4/CoFe2
+nanocomposites. The latter compound is a good system to study hard
+ferrimagnet/soft ferromagnet exchange coupling. Two steps were used to
+synthesize the bimagnetic CoFe2O4/CoFe2 nanocomposites: (i) first preparation
+of CoFe2O4 nanoparticles using the a simple hydrothermal method and (ii) second
+reduction reaction of cobalt ferrite nanoparticles using activated charcoal in
+inert atmosphere and high temperature. The phase structures, particle sizes,
+morphology, and magnetic properties of CoFe2O4 nanoparticles have been
+investigated by X-Ray diffraction (XRD), Mossbauer spectroscopy (MS),
+transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM)
+with applied field up to 3.0 kOe at room temperature and 50K. The mean diameter
+of CoFe2O4 particles is about 16 nm. Mossbauer spectra reveal two sites for
+Fe3+. One site is related to Fe in an octahedral coordination and the other one
+to the Fe3+ in a tetrahedral coordination, as expected for a spinel crystal
+structure of CoFe2O4. TEM measurements of nanocomposite show the formation of a
+thin shell of CoFe2 on the cobalt ferrite and indicate that the nanoparticles
+increase to about 100 nm. The magnetization of nanocomposite showed hysteresis
+loop that is characteristic of the exchange spring systems. A maximum energy
+product (BH)max of 1.22 MGOe was achieved at room temperature for CoFe2O4/CoFe2
+nanocomposites, which is about 115% higher than the value obtained for CoFe2O4
+precursor. The exchange-spring interaction and the enhancement of product
+(BH)max in nanocomposite CoFe2O4/CoFe2 have been discussed.",1110.4905v1
+2012-03-28,"Geometric and disorder -- type magnetic frustration in ferrimagnetic ""114"" Ferrites: Role of diamagnetic Li+ and Zn2+ cation substitution","The comparative study of the substitution of zinc and lithium for iron in the
+""114"" ferrites, YBaFe4O7 and CaBaFe4O7, shows that these diamagnetic cations
+play a major role in tuning the competition between ferrimagnetism and magnetic
+frustration in these oxides. The substitution of Li or Zn for Fe in the cubic
+phase YBaFe4O7 leads to a structural transition to a hexagonal phase
+YBaFe4-xMxO7, for M = Li (0.30 < x < 0.75) and for M = Zn (0.40 < x < 1.50). It
+is seen that for low doping values i.e. x = 0.30 (for Li) and x = 0.40 (for
+Zn), these diamagnetic cations induce a strong ferrimagnetic component in the
+samples, in contrast to the spin glass behaviour of the cubic phase. In all the
+hexagonal phases, YBaFe4-xMxO7 and CaBaFe4-xMxO7 with M = Li and Zn, it is seen
+that in the low doping regime (x ~ 0.3 to 0.5), the competition between
+ferrimagnetism and 2 D magnetic frustration is dominated by the average valency
+of iron. In contrast, in the high doping regime (x ~ 1.5), the emergence of a
+spin glass is controlled by the high degree of cationic disorder, irrespective
+of the iron valency.",1203.6220v1
+2013-05-02,Chiral properties of bismuth ferrite (BiFeO3) inferred from resonant x-ray Bragg diffraction,"A new chiral phase of ferric ions in bismuth ferrite, the only material known
+to support multiferroic behaviour at room temperature, is inferred from
+extensive sets of data gathered by resonant x-ray Bragg diffraction. Values of
+all ferric multipoles participating in a minimal model of Fe electronic
+structure are deduced from azimuthal-angle scans. Extensive sets of
+azimuthal-angle data, gathered by resonant x-ray Bragg diffraction, yield
+values of all ferric multipoles participating in a minimal model of Fe
+electronic structure. Paramagnetic (700 K) and magnetically ordered (300 K)
+phases of a single crystal of BiFeO3 have been studied with x-rays tuned near
+to the iron K-edge (7.1135 keV). At both temperatures, intensities at a Bragg
+spot forbidden in the nominal space-group, R3c, are consistent with a chiral
+motif of ferric ions in a circular cycloid propagating along (1, 1, 0)H.
+Templeton and Templeton scattering at 700 K is attributed in part to
+charge-like quadrupoles in a cycloid. The contribution is not present in a
+standard, simplified model of electronic states of the resonant ion with
+trivial cylindrical symmetry.",1305.0484v3
+2013-10-17,Insights into the Phase Diagram of Bismuth Ferrite from Quasi-Harmonic Free Energy Calculations,"We have used first-principles methods to investigate the phase diagram of
+multiferroic bismuth ferrite (BiFeO3 or BFO), revealing the energetic and
+vibrational features that control the occurrence of various relevant
+structures. More precisely, we have studied the relative stability of four
+low-energy BFO polymorphs by computing their free energies within the
+quasi-harmonic approximation, introducing a practical scheme that allows us to
+account for the main effects of spin disorder. As expected, we find that the
+ferroelectric ground state of the material (with R3c space group) transforms
+into an orthorhombic paraelectric phase (Pnma) upon heating. We show that this
+transition is not significantly affected by magnetic disorder, and that the
+occurrence of the Pnma structure relies on its being vibrationally (although
+not elastically) softer than the R3c phase. We also investigate a
+representative member of the family of nano-twinned polymorphs recently
+predicted for BFO [Prosandeev et al., Adv. Funct. Mater. 23, 234 (2013)] and
+discuss their possible stabilization at the boundaries separating the R3c and
+Pnma regions in the corresponding pressure-temperature phase diagram. Finally,
+we elucidate the intriguing case of the so-called super-tetragonal phases of
+BFO: Our results explain why such structures have never been observed in the
+bulk material, despite their being stable polymorphs of very low energy.
+Quantitative comparison with experiment is provided whenever possible, and the
+relative importance of various physical effects (zero-point motion, spin
+fluctuations, thermal expansion) and technical features (employed
+exchange-correlation energy density functional) is discussed. Our work attests
+the validity and usefulness of the quasi-harmonic scheme to investigate the
+phase diagram of this complex oxide, and prospective applications are
+discussed.",1310.4703v1
+2014-10-08,Cellular Uptake and Biocompatibility of Bismuth Ferrite Harmonic Advanced Nanoparticles,"Bismuth Ferrite (BFO) nanoparticles (BFO-NP) display interesting optical
+(nonlinear response) and magnetic properties which make them amenable for
+bio-oriented applications as intra- and extra membrane contrast agents. Due to
+the relatively recent availability of this material in well dispersed
+nanometric form, its biocompatibility was not known to date. In this study, we
+present a thorough assessment of the effects of in vitro exposure of human
+adenocarcinoma (A549), lung squamous carcinoma (NCI-H520), and acute monocytic
+leukemia (THP-1) cell lines to uncoated and poly(ethylene glycol)-coated BFO-NP
+in the form of cytotoxicity, haemolytic response and biocompatibility. Our
+results support the attractiveness of the functional-BFO towards biomedical
+applications focused on advanced diagnostic imaging.",1410.2068v1
+2015-08-31,Wireless Power Transfer for High-precision Position Detection of Railroad Vehicles,"Detection of vehicle position is critical for successful operation of
+intelligent transportation system. In case of railroad transportation systems,
+position information of railroad vehicles can be detected by GPS, track
+circuits, and so on. In this paper, position detection based on tags onto
+sleepers of the track is investigated. Position information stored in the tags
+is read by a reader placed at the bottom of running railroad vehicle. Due to
+limited capacity of battery or its alternative in the tags, power required for
+transmission of position information to the reader is harvested by the tags
+from the power wirelessly transferred from the reader. Basic mechanism in
+wireless power transfer is magnetic induction and power transfer efficiency
+according to the relative location of the reader to a tag is discussed with
+simulation results. Since power transfer efficiency is significantly affected
+by the ferromagnetic material (steel) at the bottom of the railroad vehicle and
+the track, magnetic beam shaping by ferrite material is carried out. With the
+ferrite material for magnetic beam shaping, degradation of power transfer
+efficiency due to the steel is substantially reduced. Based on the experimental
+results, successful wireless power transfer to the tag coil is possible when
+transmitted power from the reader coil is close to a few watts.",1508.07342v1
+2017-08-13,Quantum percolation phase transition and magneto-electric dipole glass in hexagonal ferrites,"Hexagonal ferrites do not only have enormous commercial impact ({\pounds}2
+billion/year in sales) due to applications that include ultra-high density
+memories, credit card stripes, magnetic bar codes, small motors and low-loss
+microwave devices, they also have fascinating magnetic and ferroelectric
+quantum properties at low temperatures. Here we report the results of tuning
+the magnetic ordering temperature in PbFe$_{12-x}$Ga$_x$O$_{19}$ to zero by
+chemical substitution $x$. The phase transition boundary is found to vary as
+$T_N \sim (1-x/x_c)^{2/3}$ with $x_c$ very close to the calculated spin
+percolation threshold which we determine by Monte Carlo simulations, indicating
+that the zero-temperature phase transition is geometrically driven. We find
+that this produces a form of compositionally-tuned, insulating, ferrimagnetic
+quantum criticality. Close to the zero temperature phase transition we observe
+the emergence of an electric-dipole glass induced by magneto-electric coupling.
+The strong frequency behaviour of the glass freezing temperature $T_m$ has a
+Vogel-Fulcher dependence with $T_m$ finite, or suppressed below zero in the
+zero frequency limit, depending on composition $x$. These quantum-mechanical
+properties, along with the multiplicity of low-lying modes near to the
+zero-temperature phase transition, are likely to greatly extend applications of
+hexaferrites into the realm of quantum and cryogenic technologies.",1708.03945v1
+2018-04-06,Effect of Substrate Temperature on Structural and Magnetic Properties of c-axis Ori-ented Spinel Ferrite Ni0.65Zn0.35Fe2O4 (NZFO) Thin Films,"Varying the substrate temperature changes structural and magnetic properties
+of spinel ferrite NZFO thin films. XRD of films grown at different temperature
+display only 004 reflections, without any secondary peaks, showing growth
+orientation along the c axis. We find an increase in crystalline quality of
+these thin films with the rise of substrate temperature. The surface topography
+of the thin films grown on various growth temperatures conditions reveal that
+these films are smooth with low roughness, however the thin films grown at 800
+C exhibit lowest average and rms roughness among all thin films. We find iron
+and nickel to be more oxidized i,e greater Fe and Ni content in films grown and
+annealed at 700 C and 800 C, compared to those grown at lower temperatures. The
+magnetic moment is observed to increase with an increase of substrate
+temperature and all thin films possess high saturation magnetization and low
+coercive field at room temperature. Films grown at 800 C exhibit a
+ferrimagnetic paramagnetic phase transition well above room temperature. The
+observed large magnetizations with soft magnetic behavior in NZFO thin films
+above room temperature suggest potential application in memory, spintronics,
+and multifunctional devices.",1804.02458v2
+2018-04-20,From Charge to Orbital Ordered Metal-Insulator Transition in Alkaline-Earth Ferrites,"While CaFeO$_3$ exhibits upon cooling a metal-insulator transition linked to
+charge ordering, SrFeO$_3$ and BaFeO$_3$ keep metallic behaviors down to very
+low temperatures. Moreover, alkaline-earth ferrites do not seem prone to
+orbital ordering in spite of the d$^4$ formal occupancy of Fe$^{4+}$. Here,
+from first-principles simulations, we show that the metal-insulator transition
+of CaFeO$_3$ is structurally triggered by oxygen rotation motions as in
+rare-earth nickelates. This not only further clarifies why SrFeO$_3$ and
+BaFeO$_3$ remain metallic but allows us to predict that an insulating
+charge-ordered phase can be induced in SrFeO$_3$ from appropriate engineering
+of oxygen rotation motions. Going further, we unveil the possibility to switch
+from the usual charge-ordered to an orbital-ordered insulating ground state
+under moderate tensile strain in CaFeO$_3$ thin films. We rationalize the
+competition between charge and orbital orderings, highlighting alternative
+possible strategies to produce such a change of ground state, also relevant to
+manganite and nickelate compounds.",1804.07584v2
+2020-07-29,All-optical nonreciprocity due to valley polarization in transition metal dichalcogenides,"Nonreciprocity and nonreciprocal optical devices play a vital role in modern
+photonic technologies by enforcing one-way propagation of light. Most
+nonreciprocal devices today are made from a special class of low-loss ferrites
+that exhibit a magneto-optical response in the presence of an external static
+magnetic field. While breaking transmission symmetry, ferrites fail to satisfy
+the need for miniaturization of photonic circuitry due to weak character of
+nonreciprocal responses at optical wavelengths and are not easy to integrate
+into on-chip photonic systems. These challenges led to the emergence of
+magnetic-free approaches relying on breaking time reversal symmetry, e.g. with
+nonlinear effects modulating optical system in time. Here, we demonstrate an
+all-optical approach to nonreciprocity based on nonlinear valley-selective
+response in transition metal dichalcogenides (TMDs). This approach overcomes
+the limitations of magnetic materials and it does not require an external
+magnetic field. We provide experimental evidence of photoinduced nonreciprocity
+in a monolayer WS2 pumped by circularly polarized light. Nonreciprocity stems
+from valley-selective exciton-exciton interactions, giving rise to nonlinear
+circular dichroism controlled by circularly polarized pump fields. Our
+experimental results reveal a significant effect even at room temperature,
+despite considerable intervalley-scattering, showing potential for practical
+applications in magnetic-free nonreciprocal platforms. As an example, we
+propose a device scheme to realize an optical isolator based on a pass-through
+silicon nitride (SiN) ring resonator integrating the optically biased TMD
+monolayer.",2007.14934v1
+2017-01-23,Size Effects of Ferroelectric and Magnetoelectric Properties of Semi-ellipsoidal Bismuth Ferrite Nanoparticles,"Bismuth ferrite (BiFeO3) is one of the most promising multiferroics with a
+sufficiently high ferroelectric (FE) and antiferromagnetic transition
+temperatures, and magnetoelectric (ME) coupling coefficient at room
+temperature, and thus it is highly sensitive to the impact of cross-influence
+of applied electric and magnetic fields. According to the urgent demands of
+nanotechnology miniaturization for ultra-high density data storage in advanced
+nonvolatile memory cells, it is very important to reduce the sizes of
+multiferroic nanoparticles in the self-assembled arrays without serious
+deterioration of their properties. We study size effects of the phase diagrams,
+FE and ME properties of semi-ellipsoidal BiFeO3 nanoparticles clamped to a
+rigid conductive substrate. The spatial distribution of the spontaneous
+polarization vector inside the nanoparticles, phase diagrams and
+paramagnetoelectric (PME) coefficient were calculated in the framework of
+modified Landau-Ginzburg-Devonshire (LGD) approach. Analytical expressions were
+derived for the dependences of the FE transition temperature, average
+polarization, linear dielectric susceptibility and PME coefficient on the
+particle sizes for a general case of a semi-ellipsoidal nanoparticles with
+three different semi-axes a, b and height c. The analyses of the obtained
+results leads to the conclusion that the size effect of the phase diagrams,
+spontaneous polarization and PME coefficient is rather sensitive to the
+particle sizes aspect ratio in the polarization direction, and less sensitive
+to the absolute values of the sizes per se.",1701.06468v1
+2017-04-14,Thermostat Influence on the Structural Development and Material Removal during Abrasion of Nanocrystalline Ferrite,"We consider a nanomachining process of hard, abrasive particles grinding on
+the rough surface of a polycrystalline ferritic work piece. Using extensive
+large-scale molecular dynamics (MD) simulations, we show that the mode of
+thermostatting, i.e., the way that the heat generated through deformation and
+friction is removed from the system, has crucial impact on tribological and
+materials related phenomena. By adopting an electron-phonon coupling approach
+to parametrize the thermostat of the system, thus including the electronic
+contribution to the thermal conductivity of iron, we can reproduce the
+experimentally measured values that yield realistic temperature gradients in
+the work piece. We compare these results to those obtained by assuming the two
+extreme cases of only phononic heat conduction and instantaneous removal of the
+heat generated in the machining interface. Our discussion of the differences
+between these three cases reveals that although the average shear stress is
+virtually temperature independent up to a normal pressure of approximately 1
+GPa, the grain and chip morphology as well as most relevant quantities depend
+heavily on the mode of thermostatting beyond a normal pressure of 0.4 GPa.
+These pronounced differences can be explained by the thermally activated
+processes that guide the reaction of the Fe lattice to the external mechanical
+and thermal loads caused by nanomachining.",1704.04384v1
+2008-07-27,Do the Tellegen particles really exist in electromagnetics?,"In 1948 Tellegen suggested that an assembly of the lined up electric-magnetic
+dipole twins can construct a new type of an electromagnetic material. Till now,
+however, the problem of creation of the Tellegen medium is a subject of strong
+discussions. An elementary symmetry analysis makes questionable an idea of a
+simple combination of two (electric and magnetic) dipoles to realize local
+materials with the Tellegen particles as structural elements. In this paper we
+show that in his search of sources with local junctions of the electrical and
+magnetic properties one cannot rely on the induced parameters of small
+electromagnetic scatterers. No near-field electromagnetic structures and
+classical motion equations for point charges give a physical basis to realize
+sources with the local junction of the electrical and magnetic properties. We
+advance a hypothesis that local magnetoelectric (ME) particles should be the
+physical objects with eigenmode oscillation spectra and non-classical symmetry
+breaking effects. Our studies convincingly prove this assumption. We show that
+a quasi-2D ferrite disk with magnetic-dipolar-mode oscillations is
+characterized by unique symmetry features with topological phases resulting in
+appearance of the ME properties. The entire ferrite disk can be characterized
+as a combined system with eigen electric and magnetic moments. The fields near
+such a particle are distinguished by special symmetry properties.",0807.4280v1
+2011-11-18,Microwave magnetoelectric fields,"We show that in a source-free subwavelength region of microwave fields there
+can exist the field structures with local coupling between the time-varying
+electric and magnetic fields differing from the electric-magnetic coupling in
+regular-propagating free-space electromagnetic waves. To distinguish such field
+structures from regular electromagnetic (EM) field structures, we term them as
+magnetoelectric (ME) fields. We study a structure and conservation laws of
+microwave ME near fields. We show that there exist sources of microwave ME near
+fields - the ME particles. These particles are represented by small quasi-2D
+ferrite disks with the magnetic-dipolar-oscillation spectra. The near fields
+originated from such particles are characterized by topologically distinctive
+power-flow vortices, non-zero helicity, and a torsion degree of freedom. Our
+studies of the microwave ME near fields are combined in two successive papers.
+In this paper we give a theoretical background of properties of the electric
+and magnetic fields inside and outside of a ferrite particle with
+magnetic-dipolar-oscillation spectra resulting in appearance of the microwave
+ME near fields. Based on the obtained structures of the ME near fields, we
+discuss effects of so-called ME interactions observed in artificial
+electromagnetic materials. In the next paper, we represent numerical and
+experimental studies of the microwave ME near fields and their interactions
+with matter.",1111.4359v1
+2016-12-24,Nonreciprocal reconfigurable microwave optomechanical circuit,"Devices that achieve nonreciprocal microwave transmission are ubiquitous in
+radar and radio-frequency communication systems, and commonly rely on
+magnetically biased ferrite materials. Such devices are also indispensable in
+the readout chains of superconducting quantum circuits as they protect
+sensitive quantum systems from the noise emitted by readout electronics. Since
+ferrite-based nonreciprocal devices are bulky, lossy, and require large
+magnetic fields, there has been significant interest in magnetic-field-free
+on-chip alternatives, such as those recently implemented using Josephson
+junctions. Here we realise reconfigurable nonreciprocal transmission between
+two microwave modes using purely optomechanical interactions in a
+superconducting electromechanical circuit. We analyse the transmission as well
+as the noise properties of this nonreciprocal circuit. The scheme relies on the
+interference in two mechanical modes that mediate coupling between microwave
+cavities. Finally, we show how quantum-limited circulators can be realized with
+the same principle. The technology can be built on-chip without any external
+magnetic field, and is hence fully compatible with superconducting quantum
+circuits. All-optomechanically-mediated nonreciprocity demonstrated here can
+also be extended to implement directional amplifiers, and it forms the basis
+towards realising topological states of light and sound.",1612.08223v3
+2017-12-15,"Tunable polymorphism of epitaxial iron oxides in the four-in-one ferroic-on-GaN system with magnetically ordered α-, γ-, ε-Fe2O3 and Fe3O4 layers","Hybridization of semiconducting and magnetic materials into a single
+heterostructure is believed to be potentially applicable to the design of novel
+functional spintronic devices. In the present work we report epitaxial
+stabilization of four magnetically ordered iron oxide phases (Fe3O4,
+{\gamma}-Fe2O3, {\alpha}-Fe2O3 and most exotic metastable {\epsilon}-Fe2O3) in
+the form of nanometer sized single crystalline films on GaN(0001) surface. The
+epitaxial growth of as many as four distinctly different iron oxide phases is
+demonstrated within the same single-target Laser MBE technological process on a
+GaN semiconductor substrate widely used for electronic device fabrication. The
+discussed iron oxides belong to a family of simple formula magnetic materials
+exhibiting a rich variety of outstanding physical properties including peculiar
+Verwey and Morin phase transitions in Fe3O4 and {\alpha}-Fe2O3 and multiferroic
+behavior in metastable magnetically hard {\epsilon}-Fe2O3 ferrite. The physical
+reasons standing behind the nucleation of a particular phase in an epitaxial
+growth process deserve interest from the fundamental point of view. The
+practical side of the presented study is to exploit the tunable polymorphism of
+iron oxides for creation of ferroic-on-semiconductor heterostructures usable in
+novel spintronic devices. By application of a wide range of experimental
+techniques the surface morphology, crystalline structure, electronic and
+magnetic properties of the single phase iron oxide epitaxial films on GaN have
+been studied. A comprehensive comparison has been made to the properties of the
+same ferrite materials in the bulk and nanostructured form reported by other
+research groups.",1712.05632v1
+2017-12-17,"Low temperature ferromagnetic properties, magnetic field induced spin order and random spin freezing effect in Ni1.5Fe1.5O4 ferrite; prepared at different pH values and annealing temperatures","We present the low temperature magnetic properties in Ni1.5Fe1.5O4 ferrite as
+the function of pH at which the material was prepared by chemical route and
+post annealing temperature. The material is a ferri or ferromagnet, but showed
+magnetic blocking and random spin freezing process on lowering the measurement
+temperature down to 5 K. The sample prepared at pH =12 and annealed at 800 ^C
+showed a sharp magnetization peak at 105 K, the superparamagnetic blocking
+temperature of the particles. The magnetization peak remained incomplete within
+measurement temperature up to 350 K for rest of the samples, although peak
+temperature was brought down by increasing applied dc field. The fitting of
+temperature dependence of coercivity data according to Kneller law suggested
+random orientation of ferromagnetic particles. The fitting of saturation
+magnetization according to Bloch law provided the exponent that largely
+deviated from 1.5, a typical value for long ranged ferromagnet. An abrupt
+increase of saturation magnetization below 50 K suggested the active role of
+frozen surface spins in low temperature magnetic properties. AC susceptibility
+data elucidated the low temperature spin freezing dynamics and exhibited the
+characters of cluster spin glass in the samples depending on pH value and
+annealing temperature.",1712.06114v1
+2019-10-24,"Solute diffusion by self-interstitial defects and radiation-induced segregation in ferritic Fe-X (X=Cr, Cu, Mn, Ni, P, Si) dilute alloys","This work investigates solute transport due to self-interstitial defects and
+radiation induced segregation tendencies in dilute ferritic alloys, by
+computing the transport coefficients of each system based on ab initio
+calculations of binding energies and migration rates. The implementation of the
+self-consistent mean field method in the KineCluE code allows to extend the
+calculation of transport coefficients to arbitrary interaction ranges, crystal
+structures, and diffusion mechanisms. The results show that the diffusivity of
+P, Mn, and Cr solute atoms is dominated by the dumbbell mechanism, that of Cu
+by vacancies, while the two mechanisms might be in competition for Ni and Si,
+despite the fact that the corresponding mixed dumbbells are not stable.
+Systematic enrichment at defect sinks is expected for P and Mn solutes due to
+dumbbell diffusion, and for Si due mainly to vacancy drag. Vacancy drag is also
+responsible for Cu and Ni enrichment below 1085 K. The RIS behavior of Cr is
+the outcome of a fine balance between dumbbell enrichment and vacancy
+depletion. Therefore, for dilute Cr concentrations global enrichment occurs
+below 540 K, and depletion above. This threshold temperature grows with solute
+concentration. The findings are in agreement with experimental observations of
+RIS and clustering phenomena, and confirm that solute-defect kinetic coupling
+plays an important role in the formation of solute clusters in reactor pressure
+vessel steels and other alloys.",1910.11440v2
+2021-01-13,An empirical approach to measuring interface energies in mixed-phase bismuth ferrite,"In complex oxide heteroepitaxy, strain engineering is a powerful tool to
+obtain phases in thin films that may be otherwise unstable in bulk. A
+successful example of this approach is mixed phase bismuth ferrite (BiFeO3)
+epitaxial thin films. The coexistence of a tetragonal-like (T-like) matrix and
+rhombohedral-like (R-like) striations provides an enhanced electromechanical
+response, along with other attractive functional behaviors. In this paper, we
+compare the energetics associated with two thickness dependent strain
+relaxation mechanisms in this system: domain walls arising from monoclinic
+distortion in the T-like phase, and the interphase boundary between the host
+T-like matrix and tilted R-like phases. Combining x-ray diffraction
+measurements with scanning probe microscopy, we extract quantitative values
+using an empirical energy balance approach. The domain wall and phase boundary
+energies are found to be 113 $\pm$ 21 and 426 $\pm$ 23 mJ.m$^{-2}$,
+respectively. These numerical estimates will help us realize designer phase
+boundaries in multiferroics, which possess colossal responses to external
+stimuli, attractive for a diverse range of functional applications.",2101.04883v2
+2017-11-27,Cavity Magnon Polaritons with Lithium Ferrite and 3D Microwave Resonators at milli-Kelvin Temperatures,"Single crystal Lithium Ferrite (LiFe) spheres of sub-mm dimension are
+examined at mK temperatures, microwave frequencies and variable DC magnetic
+field, for use in hybrid quantum systems and condensed matter and fundamental
+physics experiments. Strong coupling regimes of the photon-magnon interaction
+(cavity magnon polariton quasi-particles) were observed with coupling strength
+of up to 250 MHz at 9.5 GHz (2.6\%) with magnon linewidths of order 4 MHz (with
+potential improvement to sub-MHz values). We show that the photon-magnon
+coupling can be significantly improved and exceed that of the widely used
+Yttrium Iron Garnet crystal, due to the small unit cell of LiFe, allowing twice
+more spins per unit volume. Magnon mode softening was observed at low DC fields
+and combined with the normal Zeeman effect creates magnon spin wave modes that
+are insensitive to first order order magnetic field fluctuations. This effect
+is observed in the Kittel mode at 5.5 GHz (and another higher order mode at 6.5
+GHz) with a DC magnetic field close to 0.19 Tesla. We show that if the cavity
+is tuned close to this frequency, the magnon polariton particles exhibit an
+enhanced range of strong coupling and insensitivity to magnetic field
+fluctuations with both first order and second order insensitivity to magnetic
+field as a function of frequency (double magic point clock transition), which
+could potentially be exploited in cavity QED experiments.",1711.09980v2
+2019-02-19,"Elemental substitution tuned magneto elastoviscous behavior of nanoscale ferrite MFe2O4 M = Mn, Fe, Co, Ni based complex fluids","The present article reports the governing influence of substituting the M2
+site in nanoscale MFe2O4 spinel ferrites by different magnetic metals
+Fe,Mn,Co,Ni on magnetorheological and magneto elastoviscous behaviors of the
+corresponding magnetorheological fluids MRFs. Different doped MFe2O4
+nanoparticles have been synthesized using the polyol assisted hydrothermal
+method. Detailed steady and oscillatory shear rheology have been performed on
+the MRFs to determine the magneto-viscoelastic responses. The MRFs exhibit
+shear thinning behavior and augmented yield characteristics under influence of
+magnetic field. The steady state magnetoviscous behaviors are scaled against
+the governing Mason number and self similar response from all the MRFs have
+been noted. The MRFs conform to an extended Bingham plastic model under field
+effect. Transient magnetoviscous responses show distinct hysteresis behaviors
+when the MRFs are exposed to time varying magnetic fields. Oscillatory shear
+studies using frequency and strain amplitude sweeps exhibit predominant solid
+like behaviors under field environment. However, the relaxation behaviors and
+strain amplitude sweep tests of the MRFs reveal that while the fluids show
+solid like behaviors under field effect, they cannot be termed as typical
+elastic fluids. Comparisons show that the MnFe2O4 MRFs have superior yield
+performance among all. However, in case of dynamic and oscillatory systems,
+CoFe2O4 MRFs show the best performance. The viscoelastic responses of the MRFs
+are noted to correspond to a three element viscoelastic model. The study may
+find importance in design and development strategies of nano MRFs for different
+applications.",1902.09315v1
+2019-04-02,Magnetoelectrically driven catalytic degradation of organics,"Here, we report the catalytic degradation of organic compounds by exploiting
+the magnetoelectric (ME) nature of cobalt ferrite-bismuth ferrite (CFO-BFO)
+core-shell nanoparticles. The combination of magnetostrictive CFO with the
+multiferroic BFO gives rise to a magnetoelectric engine that purifies water
+under wireless magnetic fields via advanced oxidation processes, without
+involvement of any sacrificial molecules or co-catalysts. Magnetostrictive
+CoFe2O4 nanoparticles are fabricated using hydrothermal synthesis, followed by
+sol-gel synthesis to create the multiferroic BiFeO3 shell. We perform
+theoretical modeling to study the magnetic field induced polarization on the
+surface of magnetoelectric nanoparticles. The results obtained from these
+simulations are consistent with the experimental findings of the piezo-force
+microscopy analysis, where we observe changes in the piezoresponse of the
+nanoparticles under magnetic fields. Next, we investigate the magnetoelectric
+effect induced catalytic degradation of organic pollutants under AC magnetic
+fields and obtained 97% removal efficiency for synthetic dyes and over 85%
+removal efficiency for routinely used pharmaceuticals. Additionally, we perform
+trapping experiments to elucidate the mechanism behind the magnetic field
+induced catalytic degradation of organic pollutants by using scavengers for
+each of the reactive species. Our results indicate that hydroxyl and superoxide
+radicals are the main reactive species in the magnetoelectrically induced
+catalytic degradation of organic compounds.",1904.01271v1
+2019-08-22,Influence of structure and cation distribution on magnetic anisotropy and damping in Zn/Al doped nickel ferrites,"An in-depth analysis of Zn/Al doped nickel ferrites grown by reactive
+magnetron sputtering is relevant due to their promising characteristics for
+applications in spintronics. The material is insulating and ferromagnetic at
+room temperature with an additional low magnetic damping. By studying the
+complex interplay between strain and cation distribution their impact on the
+magnetic properties, i.e. anisotropy, damping and g-factor is unravelled. In
+particular, a strong influence of the lattice site occupation of
+Ni$^{2+}_{\text{Td}}$ and cation coordination of Fe$^{2+}_{\text{Oh}}$ on the
+intrinsic damping is found. Furthermore, the critical role of the incorporation
+of Zn$^{2+}$ and Al$^{3+}$ is evidenced by comparison with a sample of altered
+composition. Especially, the dopant Zn$^{2+}$ is evidenced as a tuning factor
+for Ni$^{2+}_{\text{Td}}$ and therefore unquenched orbital moments directly
+controlling the g-factor. A strain-independent reduction of the magnetic
+anisotropy and damping by adapting the cation distribution is demonstrated.",1908.08257v3
+2019-11-12,Diamond magnetometer enhanced by ferrite flux concentrators,"Magnetometers based on nitrogen-vacancy (NV) centers in diamond are promising
+room-temperature, solid-state sensors. However, their reported sensitivity to
+magnetic fields at low frequencies (<1 kHz) is presently >10 pT s^{1/2},
+precluding potential applications in medical imaging, geoscience, and
+navigation. Here we show that high-permeability magnetic flux concentrators,
+which collect magnetic flux from a larger area and concentrate it into the
+diamond sensor, can be used to improve the sensitivity of diamond
+magnetometers. By inserting an NV-doped diamond membrane between two ferrite
+cones in a bowtie configuration, we realize a ~250-fold increase of the
+magnetic field amplitude within the diamond. We demonstrate a sensitivity of
+~0.9 pT s^{1/2} to magnetic fields in the frequency range between 10 and 1000
+Hz, using a dual-resonance modulation technique to suppress the effect of
+thermal shifts of the NV spin levels. This is accomplished using 200 mW of
+laser power and 20 mW of microwave power. This work introduces a new dimension
+for diamond quantum sensors by using micro-structured magnetic materials to
+manipulate magnetic fields.",1911.05070v2
+2020-05-26,Nonlinear Spin Currents,"The cavity mediated spin current between two ferrite samples has been
+reported by Bai et. al. [Phys. Rev. Lett. 118, 217201 (2017)]. This experiment
+was done in the linear regime of the interaction in the presence of external
+drive. In the current paper we develop a theory for the spin current in the
+nonlinear domain where the external drive is strong so that one needs to
+include the Kerr nonlinearity of the ferrite materials. In this manner the
+nonlinear polaritons are created and one can reach both bistable and
+multistable behavior of the spin current. The system is driven into a far from
+equilibrium steady state which is determined by the details of driving field
+and various interactions. We present a variety of steady state results for the
+spin current. A spectroscopic detection of the nonlinear spin current is
+developed, revealing the key properties of the nonlinear polaritons. The
+transmission of a weak probe is used to obtain quantitative information on the
+multistable behavior of the spin current. The results and methods that we
+present are quite generic and can be used in many other contexts where cavities
+are used to transfer information from one system to another, e.g., two
+different molecular systems.",2005.12999v1
+2020-08-03,Solute hydrogen and deuterium observed at the near atomic scale in high-strength steel,"Observing solute hydrogen (H) in matter is a formidable challenge, yet,
+enabling quantitative imaging of H at the atomic-scale is critical to
+understand its deleterious influence on the mechanical strength of many
+metallic alloys that has resulted in many catastrophic failures of engineering
+parts and structures. Here, we report on the APT analysis of hydrogen (H) and
+deuterium (D) within the nanostructure of an ultra-high strength steel with
+high resistance to hydrogen embrittlement. Cold drawn, severely deformed
+pearlitic steel wires (Fe-0.98C-0.31Mn-0.20Si-0.20Cr-0.01Cu-0.006P-0.007S wt.%,
+{\epsilon}=3.1) contains cementite decomposed during the pre-deformation of the
+alloy and ferrite. We find H and D within the decomposed cementite, and at some
+interfaces with the surrounding ferrite. To ascertain the origin of the H/D
+signal obtained in APT, we explored a series of experimental workflows
+including cryogenic specimen preparation and cryogenic-vacuum transfer from the
+preparation into a state-of-the-art atom probe. Our study points to the
+critical role of the preparation, i.e. the possible saturation of H-trapping
+sites during electrochemical polishing, how these can be alleviated by the use
+of an outgassing treatment, cryogenic preparation and transfer prior to
+charging. Accommodation of large amounts of H in the under-stoichiometric
+carbide likely explains the resistance of pearlite against hydrogen
+embrittlement.",2008.00684v1
+2020-11-25,Nanoscale ferroelectricity in pseudo-cubic sol-gel derived barium titanate -- bismuth ferrite (BaTiO$_3$-BiFeO$_3$) solid solutions,"Single phase barium titanate-bismuth ferrite ((1-x)BaTi$_3$-(x)BiFe$_3$,
+BTO-BFO) solid solutions were prepared using citric acid and ethylene glycol
+assisted sol-gel synthesis method. Depending on the dopant content the samples
+are characterized by tetragonal, tetragonal-pseudocubic, pseudocubic and
+rhombohedral structure as confirmed by Raman spectroscopy and XRD measurements.
+An increase of the BFO content leads to a reduction in the cell parameters
+accompanied by a decrease in polar distortion of the unit cell wherein an
+average particle size increases from 60 up to 350 nm. Non zero piezoresponse
+was observed in the compounds with pseudocubic structure while no polar
+distortion was detected in their crystal structure using X-ray diffraction
+method. The origin of the observed non-negligible piezoresponse was discussed
+assuming a coexistence of nanoscale polar and non-polar phases attributed to
+the solid solutions with high BFO content. A coexistence of the nanoscale
+regions having polar and non-polar character is considered as a key factor to
+increase macroscopic piezoresponse in the related compounds due to increased
+mobility of the domain walls and phase boundaries.",2011.12721v1
+2021-02-16,Layer and spontaneous polarizations in perovskite oxides and their interplay in multiferroic bismuth ferrite,"We review the concept of surface charge, first in the context of the
+polarization in ferroelectric materials, and second in the context of layers of
+charged ions in ionic insulators. While the former is traditionally discussed
+in the ferroelectrics community, and the latter in the surface science
+community, we remind the reader that the two descriptions are conveniently
+unified within the modern theory of polarization. In both cases, the surface
+charge leads to electrostatic instability - the so-called ""polar catastrophe"" -
+if it is not compensated, and we review the range of phenomena that arise as a
+result of different compensation mechanisms. We illustrate these concepts using
+the example of the prototypical multiferroic bismuth ferrite, BiFeO3, which is
+unusual in that its spontaneous ferroelectric polarization and its layer
+charges can be of the same magnitude. As a result, for certain combinations of
+polarization orientation and surface terminationits surface charge is
+self-compensating. We use density functional calculations of BiFeO3 slabs and
+superlattices, analysis of high-resolution transmission electron micrographs as
+well as examples from the literature to explore the consequences of this
+peculiarity.",2102.08082v2
+2021-02-18,Modelling the relationship between deformed microstructures and static recrystallization textures: application to ferritic stainless steels,"We present an original approach for predicting the static recrystallization
+texture development during annealing of deformed crystalline materials. The
+microstructure is considered as a population of subgrains and grains whose
+sizes and boundary properties determine their growth rates. The model input
+parameters are measured directly on orientation maps maps of the deformed
+microstructure measured by electron backscattered diffraction. The anisotropy
+in subgrain properties then drives a competitive growth giving rise to the
+recrystallization texture development. The method is illustrated by a
+simulation of the static recrystallization texture development in a hot rolled
+ferritic stainless steel. The model predictions are found to be in good
+agreement with the experimental measurements, and allow for an in-depth
+investigation of the formation sequence of the recrystallization texture. A
+distinction is established between the texture components which develop due to
+favorable growth conditions and those developing due to their predominance in
+the prior deformed state. The high fraction of alpha fibre orientations in the
+recrystallized state is shown to be a consequence of their predominance in the
+deformed microstructure rather than a preferred growth mechanism. A close
+control of the fraction of these orientations before annealing is thus required
+to minimize their presence in the recrystallized state.",2102.09597v1
+2021-06-03,Macrospin model of an assembly of magnetically coupled core-shell nanoparticles,"Highly sophisticated synthesis methods and experimental techniques allow for
+precise measurements of magnetic properties of nanoparticles that can be
+reliably reproduced using theoretical models. Here, we investigate the magnetic
+properties of ferrite nanoparticles by using theoretical techniques based on
+Monte Carlo methods. We introduce three stages of sophistication in the
+macromagnetic model. First, by using tailor-made hamiltonians we study single
+nanoparticles. In a second stage, the internal structure of the nanoparticle is
+taken into consideration by defining an internal (core) and external (shell)
+region, respectively. In the last stage, an assembly of core/shell NPs are
+considered. All internal magnetic couplings such as inter and intra-atomic
+exchange interactions or magnetocrystalline anisotropies have been estimated.
+Moreover, the hysteresis loops of the aforementioned three cases have been
+calculated and compared with recent experimental measurements. In the case of
+the assembly of nanoparticles, the hysteresis loops together with the
+zero-field cooling and field cooling curves are shown to be in a very good
+agreement with the experimental data. The current model provides an important
+tool to understand the internal structure of the nanoparticles together with
+the complex internal spin interactions of the core-shell ferrite nanoparticles.",2106.01844v1
+2022-09-19,Resolving diverse oxygen transport pathways across Sr-doped lanthanum ferrite and metal-perovskite heterostructures,"Perovskite structured transition metal oxides are important technological
+materials for catalysis and solid oxide fuel cell applications. Their
+functionality often depends on oxygen diffusivity and mobility through complex
+oxide heterostructures, which can be significantly impacted by structural and
+chemical modifications, such as doping. Further, when utilized within
+electrochemical cells, interfacial reactions with other components (e.g. Ni-
+and Cr-based alloy electrodes and interconnects) can influence the perovskite's
+reactivity and ion transport, leading to complex dependencies that are
+difficult to control in real-world environments. Here we use isotopic tracers
+and atom probe tomography to directly visualize oxygen diffusion and transport
+pathways across perovskite and metal-perovskite heterostructures, i.e. (Ni-Cr
+coated) Sr-doped lanthanum ferrite (LSFO). Annealing in 18O2(g) results in
+elemental and isotopic redistributions through oxygen exchange (OE) in the LSFO
+while Ni-Cr undergoes oxidation via multiple mechanisms and transport pathways.
+Complementary density functional theory (DFT) calculations at experimental
+conditions provide rationale for OE reaction mechanisms and reveal a complex
+interplay of different thermodynamic and kinetic drivers. Our results shed
+light on the fundamental coupling of defects and oxygen transport in an
+important class of catalytic materials.",2209.09302v1
+2023-01-25,Room-temperature spin glass behavior in zinc ferrite epitaxial thin films,"Zinc ferrite (ZnFe$_{\text{2}}$O$_{\text{4}}$) epitaxial thin films were
+grown by reactive magnetron sputtering on MgAl$_{\text{2}}$O$_{\text{4}}$ and
+Al$_{\text{2}}$O$_{\text{3}}$ substrates varying a range of preparation
+parameters. The resulting structural and magnetic properties were investigated
+using a range of experimental techniques confirming epitaxial growth of
+ZnFe$_{\text{2}}$O$_{\text{4}}$ with the nominal stoichiometric composition and
+long range magnetic order at and above room temperature. The main preparation
+parameter influencing the temperature $T_{\text{f}}$ of the bifurcation between
+$M(T)$ curves under field cooled and zero-field cooled conditions was found to
+be the growth rate of the films, while growth temperature or the Ar:O$_2$ ratio
+did not systematically influence $T_{\text{f}}$. Furthermore $T_{\text{f}}$ was
+found to be systematically higher for MgAl$_{\text{2}}$O$_{\text{4}}$ as
+substrate and $T_{\text{f}}$ extends to above room temperature. While in some
+samples $T_{\text{f}}$ seems to be more likely correlated with
+superparamagentism, the highest $T_{\text{f}}$ occurs in
+ZnFe$_{\text{2}}$O$_{\text{4}}$ epitaxial films where experimental signatures
+of magnetic glassiness can be found. Element-selective X-ray magnetic circular
+dichroism measurements aim at associating the magnetic glassiness with the
+occurrence of a different valence state and lattice site incorporation of Fe
+pointing to a complex interplay of various competing magnetic interactions in
+ZnFe$_{\text{2}}$O$_{\text{4}}$.",2301.11277v1
+2023-02-10,Laser-induced magnonic band gap formation and control in YIG/GaAs heterostructure,"We demonstrate the laser-induced control over spin-wave (SW) transport in the
+magnonic crystal (MC) waveguide formed from the semiconductor slab placed on
+the ferrite film. We considered bilayer MC with periodical grooves performed on
+the top of the n-type gallium arsenide slab side that oriented to the yttrium
+iron garnet film. To observe the appearance of magnonic gap induced by laser
+radiation, the fabricated structure was studied by the use of microwave
+spectroscopy and Brillouin light-scattering. We perform detailed numerical
+studies of this structure. We showed that the optical control of the magnonic
+gaps (frequency width and position) is related to the variation of the charge
+carriers' concentration in GaAs. We attribute these to nonreciprocity of SW
+transport in the layered structure. Nonreciprocity was induced by the laser
+exposure of the GaAs slab due to SWs' induced electromagnetic field screening
+by the optically-generated charge carriers. We showed that SW dispersion,
+nonreciprocity, and magnonic band gap position and width in the
+ferrite-semiconductor magnonic crystal can be modified in a controlled manner
+by laser radiation. Our results show the possibility of the integration of
+magnonics and semiconductor electronics on the base of YIG/GaAs structures.",2302.05310v1
+2023-08-15,Microstructural and material property changes in severely deformed Eurofer-97,"Severe plastic deformation changes the microstructure and properties of
+steels, which may be favourable for their use in structural components of
+nuclear reactors. In this study, high-pressure torsion (HPT) was used to refine
+the grain structure of Eurofer-97, a ferritic/ martensitic steel. Electron
+microscopy and X-ray diffraction were used to characterise the microstructural
+changes. Following HPT, the average grain size reduced by a factor of $\sim$
+30, with a marked increase in high-angle grain boundaries. Dislocation density
+also increased by more than one order of magnitude. The thermal stability of
+the deformed material was investigated via in-situ annealing during synchrotron
+X-ray diffraction. This revealed substantial recovery between 450 K - 800 K.
+Irradiation with 20 MeV Fe-ions to $\sim$ 0.1 dpa caused a 20% reduction in
+dislocation density compared to the as-deformed material. However, HPT
+deformation prior to irradiation did not have a significant effect in
+mitigating the irradiation-induced reductions in thermal diffusivity and
+surface acoustic wave velocity of the material. These results provide a
+multi-faceted understanding of the changes in ferritic/martensitic steels due
+to severe plastic deformation, and how these changes can be used to alter
+material properties.",2308.07735v1
+2023-09-24,Hexaferrite-based permanent magnets with upper magnetic properties by cold sintering process via a non-aqueous solvent,"The incessant technological pursuit towards a more sustainable and green
+future depends strongly on permanent magnets. At present, their use is
+widespread, making it imperative to develop new processing methods that
+generate highly competitive magnetic properties reducing the fabrication
+temperatures and costs. Herein, a novel strategy for developing dense sintered
+magnets based on Sr-hexaferrites with upper functional characteristics is
+presented. An innovative cold sintering approach using glacial acetic acid as
+novelty, followed by a post-annealing at 1100 {\deg}C, achieves a densification
+of the ceramic magnets of 92% with respect to the theoretical density and
+allows controlling the particle growth. After the cold sintering process, a
+fraction of amorphous SrO is identified, in addition to a partial
+transformation to {\alpha}-Fe2O3 as secondary crystalline phase. 46 wt% of
+SrFe12O19 remains, which is mostly recuperated after the post-thermal
+treatment. These findings do not significantly modify the final structure of
+ferrite magnets, neither at short- nor long-range order. The innovative process
+has a positive impact on the magnetic properties, yielding competitive ferrite
+magnets at lower sintering temperatures with an energy efficiency of at least
+25%, which opens up a new horizon in the field of rare-earth free permanent
+magnets and new possibilities in other applications.",2309.13719v1
+2023-09-26,Duality of switching mechanisms and transient negative capacitance in improper ferroelectrics,"The recent discovery of transient negative capacitance has sparked an intense
+debate on the role of homogeneous and inhomogeneous mechanisms in polarizations
+switching. In this work, we report observation of transient negative
+capacitance in improper ferroelectric h-YbFeO3 films in a resistor-capacitor
+circuit, and a concaved shape of anomaly in the voltage wave form, in the early
+and late stage of the polarizations switching respectively. Using a
+phenomenological model, we show that the early-stage negative capacitance is
+likely due to the inhomogeneous switching involving nucleation and domain wall
+motion, while the anomaly at the late stage, which appears to be a reminiscent
+negative capacitance is the manifestation of the thermodynamically unstable
+part of the free-energy landscape in the homogeneous switching. The complex
+free-energy landscape in hexagonal ferrites may be the key to cause the abrupt
+change in polarization switching speed and the corresponding anomaly. These
+results reconcile the two seemingly conflicting mechanisms in the polarization
+switching and highlight their different roles at different stages. The unique
+energy-landscape in hexagonal ferrites that reveals the dual switching
+mechanism suggests the promising application potential in terms of negative
+capacitance.",2309.14639v1
+2024-01-26,Reactive additive capillary stamping with double network hydrogel-derived aerogel stamps under solvothermal conditions,"Integration of solvothermal reaction products into complex thin-layer
+architectures is frequently achieved by combinations of layer transfer and
+subtractive lithography, whereas direct additive substrate patterning with
+solvothermal reaction products has remained challenging. We report reactive
+additive capillary stamping under solvothermal conditions as a parallel
+contact-lithographic access to patterns of solvothermal reaction products in
+thin-layer configurations. To this end, corresponding precursor inks are
+infiltrated into mechanically robust mesoporous aerogel stamps derived from
+double-network hydrogels (DNHGs). The stamp is then brought into contact with a
+substrate to be patterned under solvothermal reaction conditions inside an
+autoclave. The precursor ink forms liquid bridges between the topographic
+surface pattern of the stamp and the substrate. Evaporation-driven enrichment
+of the precursors in these liquid bridges along with their liquid-bridge-guided
+conversion into the solvothermal reaction products yields large-area submicron
+patterns of the solvothermal reaction products replicating the stamp
+topography. As example, we prepared thin hybrid films, which contained ordered
+monolayers of superparamagnetic submicron nickel ferrite dots prepared by
+solvothermal capillary stamping surrounded by nickel electrodeposited in a
+second, orthogonal substrate functionalization step. The submicron nickel
+ferrite dots acted as magnetic hardener halving the remanence of the
+ferromagnetic nickel layer. In this way, thin-layer electromechanical systems,
+transformers and positioning systems may be customized.",2401.15013v1
+2024-02-25,High-resolution numerical-experimental comparison of heterogeneous slip activity in quasi-2D ferrite sheets,"The role of heterogeneity in the plastic flow of thin ferrite specimens is
+investigated in this study. This is done through a recently introduced quasi-2D
+experimental-numerical framework that allows for a quantitative comparison of
+the deformation fields of metal microstructures between experiments and
+simulations at a high level of detail and complexity. The method exploits
+samples that are locally ultra-thin (""2D"") and hence have a practically uniform
+microstructure through their thickness. This allows testing more complex
+loading conditions compared to uniaxial micromechanical experiments while
+avoiding the complexity of an unknown subsurface microstructure, which limits
+comparisons between experiments and simulations in traditional integrated
+approaches at the level of the polycrystalline microstructure. The present
+approach enables to study the effect of microstructural features such as grain
+boundaries. To study the role of stochastic fluctuations, a constitutive model
+is employed which introduces random heterogeneity into a crystal plasticity
+model. A detailed analysis of the simulations is performed at the level of
+individual slip systems. Since both experimental and numerical results are
+susceptible to stochastic fluctuations, the outcomes of many simulations are
+compared to the experimentally obtained result. This comparison allows us to
+determine how a single experiment relates to an ensemble of simulations.
+Additionally, results obtained with a conventional crystal plasticity model are
+considered. The analysis reveals that the heterogeneity in the plasticity model
+is essential for accurately capturing the deformation mechanisms.",2402.16199v1
+2019-07-26,Stabilization of $\varepsilon$-Fe$_2$O$_3$ epitaxial layer on MgO(111)/GaN via an intermediate $γ$-Fe$_2$O$_3$-phase,"In the present study we have demonstrated epitaxial stabilization of the
+metastable magnetically-hard $\varepsilon$-Fe$_2$O$_3$ phase on top of a thin
+MgO(111) buffer layer grown onto the GaN (0001) surface. The primary purpose to
+introduce a 4\,nm-thick buffer layer of MgO in between Fe$_2$O$_3$ and GaN was
+to stop thermal migration of Ga into the iron oxide layer. Though such
+migration and successive formation of the orthorhombic GaFeO$_3$ was supposed
+earlier to be a potential trigger of the nucleation of the isostructural
+$\varepsilon$-Fe$_2$O$_3$, the present work demonstrates that the growth of
+single crystalline uniform films of epsilon ferrite by pulsed laser deposition
+is possible even on the MgO capped GaN. The structural properties of the 60\,nm
+thick Fe$_2$O$_3$ layer on MgO / GaN were probed by electron and x-ray
+diffraction, both suggesting that the growth of $\varepsilon$-Fe$_2$O$_3$ is
+preceded by formation of a thin layer of $\gamma$-Fe$_2$O$_3$. The presence of
+the magnetically hard epsilon ferrite was independently confirmed by
+temperature dependent magnetometry measurements. The depth-resolved x-ray and
+polarized neutron reflectometry reveal that the 10\,nm iron oxide layer at the
+interface has a lower density and a higher magnetization than the main volume
+of the $\varepsilon$-Fe$_2$O$_3$ film. The density and magnetic moment depth
+profiles derived from fitting the reflectometry data are in a good agreement
+with the presence of the magnetically degraded $\gamma$-Fe$_2$O$_3$ transition
+layer between MgO and $\varepsilon$-Fe$_2$O$_3$. The natural occurrence of the
+interface between magnetoelectric $\varepsilon$- and spin caloritronic
+$\gamma$- iron oxide phases can enable further opportunities to design novel
+all-oxide-on-semiconductor devices.",1907.11611v2
+2021-02-05,Inter-valence charge transfer and charge transport in the spinel ferrite ferromagnetic semiconductor Ru-doped CoFe$_2$O$_4$,"Inter-valence charge transfer (IVCT) is electron transfer between two metal
+$M$ sites differing in oxidation states through a bridging ligand: $M^{n+1} +
+M'^{m} \rightarrow M^{n} + M'^{m+1}$. It is considered that IVCT is related to
+the hopping probability of electron (or the electron mobility) in solids. Since
+controlling the conductivity of ferromagnetic semiconductors (FMSs) is a key
+subject for the development of spintronic device applications, the manipulation
+of the conductivity through IVCT may become a new approach of band engineering
+in FMSs. In Ru-doped cobalt ferrite CoFe$_2$O$_4$ (CFO) that shows
+ferrimagnetism and semiconducting transport properties, the reduction of the
+electric resistivity is attributed to both the carrier doping caused by the Ru
+substitution for Co and the increase of the carrier mobility due to
+hybridization between the wide Ru $4d$ and the Fe $3d$ orbitals. The latter is
+the so-called IVCT mechanism that is charge transfer between the mixed valence
+Fe$^{2+}$/Fe$^{3+}$ states facilitated by bridging Ru $4d$ orbital: Fe$^{2+}$ +
+Ru$^{4+}$ $\leftrightarrow$ Fe$^{3+}$ + Ru$^{3+}$. To elucidate the emergence
+of the IVCT state, we have conducted x-ray absorption spectroscopy (XAS) and
+resonant photoemission spectroscopy (RPES) measurements on non-doped CFO and
+Co$_{0.5}$Ru$_{0.5}$Fe$_2$O$_4$ (CRFO) thin films. The observations of the XAS
+and RPES spectra indicate that the presence of the mixed valence
+Fe$^{2+}$/Fe$^{3+}$ state and the hybridization between the Fe $3d$ and Ru $4d$
+states in the valence band. These results provide experimental evidence for the
+IVCT state in CRFO, demonstrating a novel mechanism that controls the electron
+mobility through hybridization between the $3d$ transition-metal cations with
+intervening $4d$ states.",2102.03020v1
+2021-02-24,"Gamma irradiated nanostructured NiFe2O4: Effect of gamma-photon on morphological, structural, optical and magnetic properties","The current manuscript highlights the preparation of NiFe2O4 nanoparticles by
+adopting sol-gel auto combustion route. The prime focus of this study is to
+investigate the impact of gamma irradiation on the microstructural,
+morphological, functional, optical and magnetic characteristics. The resulted
+NiFe2O4 products have been characterized employing numerous instrumental
+equipments such as FESEM, XRD, UV visible spectroscopy, FTIR and PPMS for a
+variety of gamma ray doses (0 kGy, 25 kGy and 100 kGy). FESEM micrographs
+illustrate the aggregation of ferrite nanoparticles in pristine NiFe2O4 product
+having an average particle size of 168 nm and the surface morphology is altered
+after exposure to gamma-irradiation. XRD spectra have been analyzed employing
+Rietveld method and the results of the XRD investigation reveal the desired
+phases (cubic spinel phases) of NiFe2O4 with observing other transitional
+phases. Several microstructural parameters such as bond length, bond angle,
+hopping length etc. have been determined from the analysis of Rietveld method.
+This study reports that the gamma irradiations demonstrate a great influence on
+optical bandgap energy and it varies from 1.80 and 1.89 eV evaluated via K M
+function. FTIR measurement depicts a proof for the persistence of Ni-O and Fe-O
+stretching vibrations within the respective products and thus indicating the
+successful development of NiFe2O4. The saturation magnetization (MS) of
+pristine Ni ferrite product is noticed to be 28.08 emug-1. A considerable
+increase in MS is observed in case of low gamma-dose (25 kGy) and a decrement
+nature is disclosed after the result of high dose of gamma irradiation
+(100kGy).",2102.12385v1
+2021-05-19,Magnetic structure and multiferroicity of Sc-substituted hexagonal YbFeO$_3$,"Hexagonal rare-earth ferrite RFeO$_3$ family represents a unique class of
+multiferroics exhibiting weak ferromagnetism, and a strong coupling between
+magnetism and structural trimerization is predicted. However, the hexagonal
+structure for RFeO$_3$ remains metastable in conventional condition. We have
+succeeded in stabilizing the hexagonal structure of polycrystalline YbFeO$_3$
+by partial Sc substitution of Yb. Using bulk magnetometry and neutron
+diffraction, we find that Yb$_{0.42}$Sc$_{0.58}$FeO$_3$ orders into a canted
+antiferromagnetic state with the Neel temperature $T_N$ ~ 165 K, below which
+the $Fe^{3+}$ moments form the triangular configuration in the $ab$-plane and
+their in-plane projections are parallel to the [100] axis, consistent with
+magnetic space group $P$6$_{3}$$c'm'$. It is determined that the spin-canting
+is aligned along the $c$-axis, giving rise to the weak ferromagnetism.
+Furthermore, the $Fe^{3+}$ moments reorient toward a new direction below
+reorientation temperature $T_R$ ~ 40 K, satisfying magnetic subgroup
+$P$6$_{3}$, while the $Yb^{3+}$ moments order independently and
+ferrimagnetically along the $c$-axis at the characteristic temperature $T_{Yb}$
+~ 15 K. Interestingly, reproducible modulation of electric polarization induced
+by magnetic field at low temperature is achieved, suggesting that the delicate
+structural distortion associated with two-up/one-down buckling of the
+Yb/Sc-planes and tilting of the FeO$_5$ bipyramids may mediate the coupling
+between ferroelectric and magnetic orders under magnetic field. The present
+work represents a substantial progress to search for high-temperature
+multiferroics in hexagonal ferrites and related materials.",2105.08931v1
+2022-01-18,"A Nanomechanical Testing Framework Yielding Front&Rear-Sided, High-Resolution, Microstructure-Correlated SEM-DIC Strain Fields","The continuous development of new multiphase alloys with improved mechanical
+properties requires quantitative microstructure-resolved observation of the
+nanoscale deformation mechanisms at, e.g., multiphase interfaces. This calls
+for a combinatory approach beyond advanced testing methods such as microscale
+strain mapping on bulk material and micrometer sized deformation tests of
+single grains. We propose a nanomechanical testing framework that has been
+carefully designed to integrate several state-of-the-art testing and
+characterization methods: (i) well-defined nano-tensile testing of carefully
+selected and isolated multiphase specimens, (ii) front&rear-sided SEM-EBSD
+microstructural characterization combined with front&rear-sided in-situ SEM-DIC
+testing at very high resolution enabled by a recently developed InSn nano-DIC
+speckle pattern, (iii) optimized DIC strain mapping aided by application of SEM
+scanning artefact correction and DIC deconvolution for improved spatial
+resolution, (iv) a novel microstructure-to-strain alignment framework to
+deliver front&rear-sided, nanoscale, microstructure-resolved strain fields, and
+(v) direct comparison of microstructure, strain and SEM-BSE damage maps in the
+deformed configuration. Demonstration on a micrometer-sized dual-phase steel
+specimen, containing an incompatible ferrite-martensite interface, shows how
+the nanoscale deformation mechanisms can be unraveled. Discrete
+lath-boundary-aligned martensite strain localizations transit over the
+interface into diffuse ferrite plasticity, revealed by the nanoscale
+front&rear-sided microstructure-to-strain alignment and optimization of DIC
+correlations. The proposed framework yields front&rear-sided aligned
+microstructure and strain fields providing 3D interpretation of the deformation
+and opening new opportunities for unprecedented validation of advanced
+multiphase simulations.",2201.08249v2
+2022-01-21,A Detailed Investigation of the Onion Structure of Exchanged Coupled Magnetic Fe(3-delta)O4@CoFe2O4@Fe(3-delta)O4 Nanoparticles,"Nanoparticles (NPs) which combine several magnetic phases offer wide
+perspectives for cutting edge applications because of the high modularity of
+their magnetic properties. Besides the addition of the magnetic characteristics
+intrinsic to each phase, the interface that results from core-shell and,
+further, from onion structures leads to synergistic properties such as magnetic
+exchange coupling. Such a phenomenon is of high interest to overcome the
+superparamagnetic limit of iron oxide NPs which hampers potential applications.
+In this manuscript, we report on the design of NPs with an onion-like structure
+which have been scarcely reported yet. These NPs consist in a Fe(3_delta)O4
+core covered by a first shell of CoFe2O4 and a second shell of Fe(3-delta)O4.
+They were synthesized by a multi-step seed mediated growth approach. Although
+TEM micrographs clearly show the growth of each shell from the iron oxide core,
+core sizes and shell thicknesses markedly differ from what is suggested by the
+size increase. We investigated very precisely the structure of NPs in
+performing high resolution (scanning) TEM imaging and GPA. The chemical
+composition and spatial distribution of atoms were studied by EELS. The
+chemical environment and oxidation state of cations were investigated by
+M\""ossbauer spectrometry, soft XAS and XMCD. These techniques allowed us to
+estimate the increase of Fe2+ content in the iron oxide core of the core@shell
+structure and the increase of the cobalt ferrite shell thickness in the
+core@shell@shell one, while the iron oxide shell appears to be much thinner
+than expected. Thus, the modification of the chemical composition as well as
+the size of the Fe(3-delta)O4 core and the thickness of the cobalt ferrite
+shell have a high impact on the magnetic properties. Furthermore, the growth of
+the iron oxide shell also markedly modifies the magnetic properties of the
+core-shell NPs.",2201.08923v1
+2023-06-19,Onion-like Fe3O4/MgO/CoFe2O4 magnetic nanoparticles: new ways to control magnetic coupling between soft/hard phases,"The control of the magnetization inversion dynamics is one of the main
+challenges driving the design of new nanostructured magnetic materials for
+magnetoelectronic applications. Nanoparticles with onion-like architecture
+offer a unique opportunity to expand the possibilities allowing to combine
+different phases at the nanoscale and also modulate the coupling between
+magnetic phases by introducing spacers in the same structure. Here we report
+the fabrication, by a three-step high temperature decomposition method, of
+Fe3O4/MgO/CoFe2O4 onio-like nanoparticles and their detailed structural
+analysis, elemental compositional maps and magnetic response. The
+core/shell/shell nanoparticles present epitaxial growth and cubic shape with
+overall size of (29+-6) nm. These nanoparticles are formed by cubic iron oxide
+core of (22+-4) nm covered by two shells, the inner of magnesium oxide and the
+outer of cobalt ferrite of ~1 and ~2.5 nm of thickness, respectively. The
+magnetization measurements show a single reversion magnetization curve and the
+enhancement of the coercivity field, from HC~608 Oe for the Fe3O4/MgO to
+HC~5890 Oe to the Fe3O4/MgO/CoFe2O4 nanoparticles at T=5 K, ascribed to the
+coupling between both ferrimagnetic phases with a coupling constant of =2
+erg/cm2. The system also exhibits exchange bias effect, where the exchange bias
+field increases up to HEB~2850 Oe at 5 K accompanied with the broadening of the
+magnetization loop of HC~6650 Oe. This exchange bias effect originates from the
+freezing of the surface spins below the freezing temperature TF=32 K that
+pinned the magnetic moment of the cobalt ferrite shell.",2306.13108v1
+2023-06-29,Registration between DCT and EBSD datasets for multiphase microstructures,"The ability to characterise the three-dimensional microstructure of
+multiphase materials is essential for understanding the interaction between
+phases and associated materials properties. Here, laboratory-based
+diffraction-contrast tomography (DCT), a recently-established materials
+characterization technique that can determine grain phases, morphologies,
+positions and orientations in a voxel-based reconstruction method, was used to
+map part of a dual-phase steel alloy sample. To assess the resulting
+microstructures that were produced by the DCT technique, an EBSD map was
+collected within the same sample volume. To identify the 2D slice of the 3D DCT
+reconstruction that best corresponded to the EBSD map, a novel registration
+technique based solely on grain-averaged orientations was developed -- this
+registration technique requires very little a priori knowledge of dataset
+alignment and can be extended to other techniques that only recover
+grain-averaged orientation data such as far-field 3D X-ray diffraction
+microscopy. Once the corresponding 2D slice was identified in the DCT dataset,
+comparisons of phase balance, grain size, shape and texture were performed
+between DCT and EBSD techniques. More complicated aspects of the
+microstructural morphology such as grain boundary shape and grains less than a
+critical size were poorly reproduced by the DCT reconstruction, primarily due
+to the difference in resolutions of the technique compared with EBSD. However,
+lab-based DCT is shown to accurately determine the centre-of-mass position,
+orientation, and size of the large grains for each phase present, austenite and
+martensitic ferrite. The results reveals a complex ferrite grain network of
+similar crystal orientations that are absent from the EBSD dataset. Such detail
+demonstrates that lab-based DCT, as a technique, shows great promise in the
+field of multi-phase material characterization.",2306.17011v1
+2023-09-19,Remanence Increase in SrFe$_{12}$O$_{19}$/Fe Exchange-Decoupled Hard-Soft Composite Magnets Owing to Dipolar Interactions,"In the search for improved permanent magnets, fueled by the geostrategic and
+environmental issues associated with rare-earth-based magnets, magnetically
+hard (high anisotropy)-soft (high magnetization) composite magnets hold promise
+as alternative magnets that could replace modern permanent magnets, such as
+rare-earth-based and ceramic magnets, in certain applications. However, so far,
+the magnetic properties reported for hard-soft composites have been
+underwhelming. Here, an attempt to further understand the correlation between
+magnetic and microstructural properties in strontium ferrite-based composites,
+hard SrFe$_{12}$O$_{19}$ (SFO) ceramics with different contents of Fe particles
+as soft phase, both in powder and in dense injection molded magnets, is
+presented. In addition, the influence of soft phase particle dimension, in the
+nano- and micron-sized regimes, on these properties is studied. While Fe and
+SFO are not exchange-coupled in our magnets, a remanence that is higher than
+expected is measured. In fact, in composite injection molded anisotropic
+(magnetically oriented) magnets, remanence is improved by 2.4% with respect to
+a pure ferrite identical magnet. The analysis of the experimental results in
+combination with micromagnetic simulations allows us to establish that the type
+of interaction between hard and soft phases is of a dipolar nature, and is
+responsible for the alignment of a fraction of the soft spins with the
+magnetization of the hard. The mechanism unraveled in this work has
+implications for the development of novel hard-soft permanent magnets.",2309.10676v1
+2024-03-07,"Effects of mechanical stress, chemical potential, and coverage on hydrogen solubility during hydrogen enhanced decohesion of ferritic steel grain boundaries: A first-principles study","Hydrogen enhanced decohesion (HEDE) is one of the many mechanisms of hydrogen
+embrittlement, a phenomenon which severely impacts structural materials such as
+iron and iron alloys. Grain boundaries (GBs) play a critical role in this
+mechanism, where they can provide trapping sites or act as hydrogen diffusion
+pathways. The interaction of H with GBs and other crystallographic defects, and
+thus the solubility and distribution of H in the microstructure, depends on the
+concentration, chemical potential and local stress. Therefore, for a
+quantitative assessment of HEDE, a generalized solution energy in conjunction
+with the cohesive strength as a function of hydrogen coverage is needed. In
+this work, we carry out density functional theory calculations to investigate
+the influence of H on the decohesion of the $\Sigma$5(310)[001] and
+$\Sigma$3(112)[1$\bar{1}$0] symmetrical tilt GBs in bcc Fe, as examples for
+open and close-packed GB structures. A method to identify the segregation sites
+at the GB plane is proposed. The results indicate that at higher local
+concentrations, H leads to a significant reduction of the cohesive strength of
+the GB planes, significantly more pronounced at the $\Sigma$5 than at the
+$\Sigma$3 GB. Interestingly, at finite stress the $\Sigma$3 GB becomes more
+favorable for H solution, as opposed to the case of zero stress, where the
+$\Sigma$5 GB is more attractive. This suggests that under certain conditions
+stresses in the microstructure can lead to a re-distribution of H to the
+stronger grain boundary, which opens a new path to designing H-resistant
+microstructures. To round up our study, we investigate the effects of typical
+alloying elements in ferritic steel, C, V, Cr and Mn, on the solubility of H
+and the strength of the GBs.",2403.04741v1
+1998-06-24,A Scanned Perturbation Technique For Imaging Electromagnetic Standing Wave Patterns of Microwave Cavities,"We have developed a method to measure the electric field standing wave
+distributions in a microwave resonator using a scanned perturbation technique.
+Fast and reliable solutions to the Helmholtz equation (and to the Schrodinger
+equation for two dimensional systems) with arbitrarily-shaped boundaries are
+obtained. We use a pin perturbation to image primarily the microwave electric
+field amplitude, and we demonstrate the ability to image broken time-reversal
+symmetry standing wave patterns produced with a magnetized ferrite in the
+cavity. The whole cavity, including areas very close to the walls, can be
+imaged using this technique with high spatial resolution over a broad range of
+frequencies.",9806023v1
+2002-06-21,Multiple bound states in scissor-shaped waveguides,"We study bound states of the two-dimensional Helmholtz equations with
+Dirichlet boundary conditions in an open geometry given by two straight leads
+of the same width which cross at an angle $\theta$. Such a four-terminal
+junction with a tunable $\theta$ can realized experimentally if a right-angle
+structure is filled by a ferrite. It is known that for $\theta=90^o$ there is
+one proper bound state and one eigenvalue embedded in the continuum. We show
+that the number of eigenvalues becomes larger with increasing asymmetry and the
+bound-state energies are increasing as functions of $\theta$ in the interval
+$(0,90^o)$. Moreover, states which are sufficiently strongly bent exist in
+pairs with a small energy difference and opposite parities. Finally, we discuss
+how with increasing $\theta$ the bound states transform into the quasi-bound
+states with a complex wave vector.",0206397v2
+2003-01-22,Current and vorticity auto correlation functions in open microwave billiards,"Using the equivalence between the quantum-mechanical probability density in a
+quantum billiard and the Poynting vector in the corresponding microwave system,
+current distributions were studied in a quantum dot like cavity, as well as in
+a Robnik billiard with lambda=0.4, and an introduced ferrite cylinder. Spatial
+auto correlation functions for currents and vorticity were studied and compared
+with predictions from the random-superposition-of-plane-waves hypothesis. In
+addition different types of vortex neighbour spacing distributions were
+determined and compared with theory.",0301411v2
+2004-03-15,Superparamagnetic relaxation in Cu_{x}Fe_{3-x}O_{4} (x=0.5 and x=1) nanoparticles,"The scope of this article is to report very detailed results of the
+measurements of magnetic relaxation phenomena in the new
+Cu$_{0.5}$Fe$_{2.5}$O$_{4}$ nanoparticles and known CuFe$_{2}$O$_{4}$
+nanoparticles. The size of synthesized particles is (6.5$\pm $1.5)nm. Both
+samples show the superparamagnetic behaviour, with the well-defined phenomena
+of blocking of magnetic moment. This includes the splitting of
+zero-field-cooled and field-cooled magnetic moment curves, dynamical
+hysteresis, slow quasi-logarithmic relaxation of magnetic moment below blocking
+temperature. The scaling of the magnetic moment relaxation data at different
+temperatures confirms the applicability of the simple thermal relaxation model.
+The two copper-ferrites with similar structures show significantly different
+magnetic anisotropy density and other magnetic properties. Investigated systems
+exhibit the consistency of all obtained results.",0403358v1
+2004-06-30,Weak ferromagnetism and magnetoelectric coupling in bismuth ferrite,"We analyze the coupling between the ferroelectric and magnetic order
+parameters in the magnetoelectric multiferroic BiFeO_3 using density functional
+theory within the local spin density approximation and the LSDA+U method. We
+show that weak ferromagnetism of the Dzyaloshinskii-Moriya type occurs in this
+material, and we analyze the coupling between the resulting magnetization and
+the structural distortions. We explore the possibility of
+electric-field-induced magnetization reversal and show that, although it is
+unlikely to be realized in BiFeO_3, it is not in general impossible. Finally we
+outline the conditions that must be fulfilled to achieve switching of the
+magnetization using an electric field.",0407003v1
+2004-12-13,Space-Time Parity Violation and Magnetoelectric Interactions in Antiferromagnets,"The properties of antiferromagnetic materials with violated space-time parity
+are considered. Particular attention is given to the bismuth ferrite BiFeO3
+ferroelectric magnet. This material is distinguished from other
+antiferromagnets in that the inversion center is absent in its crystal and
+magnetic structures. This circumstance gives rise to the diversified and
+unusual properties, namely, to the appearance of a spatially modulated spin
+structure and to the unique possibility of the linear magnetoelectric effect
+coexisting with a weak ferromagnetic moment. The magnetic-induced phase
+transitions accompanied by the suppression of the modulated spin structure and
+appearance of a number of new and unusual effects are considered. These are the
+linear magnetoelectric effect and the appearance of a toroidal moment and a
+weak ferromagnetic moment of the magnetoelectric nature.",0412318v1
+2005-05-06,Oxygen diffusion in nanostructured perovskites,"Nonstoichiometric perovskite-related oxides (such as ferrites and cobaltites,
+etc.) are characterized by fast oxygen transport at ambient temperatures, which
+relates to the microstructural texturing of these materials, consisting wholly
+of nanoscale microdomains.
+  We have developed an inhomogeneous diffusion model to describe the kinetics
+of oxygen incorporation into nanostructured oxides. Nanodomain boundaries are
+assumed to be the high diffusivity paths for oxygen transport whereas diffusion
+into the domains proceeds much slower. Using Laplace transform methods, an
+exact solution is found for a ramped stepwise potential, allowing fitting of
+the experimental data to theoretical curves (in Laplace transforms).
+  A further model generalization is considered by introducing additional
+parameters for the size distribution of domains and particles.
+  The model has been applied for qualitative evaluation of oxygen diffusion
+parameters from the data on wet electrochemical oxidation of nano-structured
+perovskite SrCo_0.5Fe_0.2Ta_0.3O_{3-y} samples.",0505149v2
+2006-02-27,Excitation of vortices using linear and nonlinear magnetostatic waves,"It is shown that stationary vortex structures can be excited in a ferrite
+film. This is the first proposal for creating vortex structures in the
+important cm and mm wavelength ranges. It is shown that both linear and
+nonlinear structures can be excited using a three-beam interaction created with
+circular antennae. These give rise to a special phase distribution created by
+linear and nonlinear mixing. An interesting set of three clockwise rotating
+vortices joined by one counter-rotating one presents itself in the linear
+regime: a scenario that is only qualitatively changed by the onset of
+nonlinearity. It is pointed out that control of the vortex structure, through
+parametric coupling, based upon a microwave resonator, is possible and that
+there are many interesting possibilities for applications.",0602637v1
+2007-01-14,Sr1.5Ba0.5Zn2Fe12O22 Hexaferrites Ferromagnetic Resonance and Nonlinear Excitation for Magneto-Electric Devices,"A magneto electric (ME) effect was reported [1] for the insulator material of
+helimagnetic hexaferrite of Sr1.5Ba0.5Zn2Fe12O22. In this study we are
+interested in investigating this materials ferromagnetic resonance to define
+its internal anisotropy fields. By using a vibrating sample magnetometer (VSM)
+and ferromagnetic resonance (FMR) analysis we realized that this helical
+hexaferrite has about -0.5 kOe exchange anisotropy field of HE. Also, by using
+an alternative free energy model we derived this materials Polder tensor and
+its ferromagnetic resonance condition. Meanwhile, we were able to show a
+potential magneto electric coupling by nonlinear excitation of planar helical
+hexaferrite, in which a magnetic nonlinear excitation is integrated into
+dielectric permittivity.
+  Index Terms, Ferrites, ferromagnetic resonances, and magnetic nonlinear
+excitations.",0701309v2
+2007-01-29,Parameters of the Dzyaloshinsky-Moriya type weak ferromagnetism for some perovskite compounds,"Compounds with distorted perovskite structure of the 4-f and 3-d transition
+metals with the common formula LnTO3 (where Ln is rare-earth element, T is an
+element from the Fe group) are the most multifold binary oxides of these two
+groups elements. Wide range of stability for this structure allows the
+realization of combinations of the Lanthanides with all the transition metals
+except the Nickel. Quite interesting physical phenomena take place in these
+oxides like charge and orbital ordering; relatively independent magnetic
+lattices of the both metals; particular magnetic structures; high optical
+indicators; giant magneto-resistance; peculiar dielectric and ferroelectric
+properties etc. We have investigated the magnetic properties of pure ferrites
+and chromium-based materials as well as of some mixed type oxides like
+HoxTb1-xO3, HoMnxFe1-xO3, HoMnxCr1-xO3 and DyFexCr1-xO3.",0701708v1
+2006-04-13,Exchange Bias and Vertical Shift in CoFe2O4 nanoparticles,"Magnetic properties of core-shell cobalt ferrite nanoparticles 15 to 48nm
+prepared by a sol-gel route have been studied. It is shown that the coercivity
+follows non-monotonic size dependence varying as 1/d above the maximum (d is
+the particle size). Field cooled magnetization exhibited both horizontal
+(exchange bias) and vertical shifts. The exchange bias is understood as
+originating at the interface between a surface region with structural and spin
+disorder and a core ferrimagnetic region. The dependence of the exchange bias
+and vertical shifts on the particle sizes and cooling fields are found to have
+significant differences and the differences are explained in the light of
+recent results which suggest that both weakly and strongly pinned spins are
+present at the interface. It is suggested that the exchange bias is dominated
+by the weakly pinned spins while the vertical shift is affected by the strongly
+pinned ones.",0604027v1
+2000-08-17,RF Cell Modeling and Experiments for Wakefield Minimization in DARHT-II,"Electron beams of linear induction accelerators experience deflective forces
+caused by RF fields building up as a result of accelerating cavities of finite
+size. These forces can significantly effect the beam when a long linac composed
+of identical cells is assembled. Recent techniques in computational modeling,
+simulation, and experiments for 20 MeV DARHT-II (Dual Axis Radiographic
+Hydrodynamic Test) accelerator cells were found to reduce the wakefield
+impedance of the cells from 800 ohms/meter to 350 ohms/meter and experimental
+results confirm the results of the modeling efforts. Increased performance of
+the cell was obtained through a parametric study of the accelerator structure,
+materials, material tuning, and geometry. As a result of this effort, it was
+found that thickness-tuned ferrite produced a 50% deduction in the wakefield
+impedance in the low frequency band and was easily tunable based on the
+material thickness. It was also found that shaped metal sections allow for
+high-Q resonances to be de-tuned, thus decreasing the amplitude of the
+resonance and increasing the cell s performance. For the geometries used for
+this cell, a roughly 45 degree angle had the best performance in affecting the
+wakefield modes.",0008099v2
+2004-12-14,"Effects of Static Magnetic Field on Growth of Leptospire, Leptospira interrogans serovar canicola: Immunoreactivity and Cell Division","The effects of the exposure of the bacterium, Leptospira interrogans serovar
+canicola to a constant magnetic field with magnetic flux density from a
+permanent ferrite magnet = 140 mT were studied. Changes in Leptospira cells
+after their exposure to the field were determined on the basis of changes in
+their growth behavior and agglutination immunoreactivity with a homologous
+antiserum using darkfield microscopy together with visual imaging. The data
+showed that the exposed Leptospira cells have lower densities and lower
+agglutination immunoreactivity than the unexposed control group. Interestingly,
+some of the exposed Leptospira cells showed abnormal morphologies such as large
+lengths. We discussed some of the possible reasons for these observations.",0412076v1
+2007-07-26,Room temperature spin filtering in epitaxial cobalt-ferrite tunnel barriers,"We report direct experimental evidence of room temperature spin filtering in
+magnetic tunnel junctions (MTJs) containing CoFe2O4 tunnel barriers via
+tunneling magnetoresistance (TMR) measurements.
+Pt(111)/CoFe2O4(111)/gamma-Al2O3(111)/Co(0001) fully epitaxial MTJs were grown
+in order to obtain a high quality system, capable of functioning at room
+temperature. Spin polarized transport measurements reveal significant TMR
+values of -18% at 2 K and -3% at 290 K. In addition, the TMR ratio follows a
+unique bias voltage dependence that has been theoretically predicted to be the
+signature of spin filtering in MTJs containing magnetic barriers. CoFe2O4
+tunnel barriers therefore provide a model system to investigate spin filtering
+in a wide range of temperatures.",0707.3823v2
+2007-11-26,Electronic structures and lattice dynamics of BaTiO3 and BiFeO3 : a comparative first-principles study,"First-principles calculations were performed to investigate the ferroelectric
+properties of barium titanate and bismuth ferrite, as well as phonon dispersion
+of BaTiO3, using density functional theory and density functional perturbation
+theory. Results show that the strong hybridization of Ti-O and Bi-O lead to the
+corresponding mechanisms for stabilizing the distorted structure. The
+spontaneous polarization of 59.4 \mu C/cm2 and 27.6 \mu C/cm2 were calculated
+for BiFeO3 and BaTiO3 respectively, using berry phase method within the modern
+theory of polarization. The stereochemical activity of Bi-6s long-pair, which
+was the driven mechanism for ferroelectricity in BiFeO3, was able to produce
+greater polarization than the Ti off-centring displacement in BaTiO3. New
+multiferroic perovskite type materials combined with these two ferroelectric
+instabilities were predicted to have a better ferromagnetic ordering in
+comparison with BiFeO3.",0711.3942v3
+2008-01-10,Linear and Nonlinear Optical constants of BiFeO_3,"Using spectroscopic ellipsometry, the refractive index and absorption versus
+wavelength of the ferroelectric antiferromagnet Bismuth Ferrite, BiFeO_3 is
+reported. The material has a direct band-gap at 442 nm wavelength (2.81 eV).
+Using optical second harmonic generation, the nonlinear optical coefficients
+were determined to be d_15/d_22 = 0.20 +/- 0.01, d_31/d_22 = 0.35 +/- 0.02,
+d_33/d_22 = -11.4 +/- 0.20 and |d_22| = 298.4 +/- 6.1 pm/V at a fundamental
+wavelength of 800 nm.",0801.1626v1
+2008-04-28,The role of carbon segregation on nanocrystallisation of pearlitic steels processed by severe plastic deformation,"The nanostructure and the carbon distribution in a pearlitic steel processed
+by torsion under high pressure was investigated by three-dimensional atom
+probe. In the early stage of deformation (shear strain of 62),
+off-stoichiometry cementite was analysed close to interphase boundaries and a
+strong segregation of carbon atoms along dislocation cell boundaries was
+observed in the ferrite. At a shear strain of 300, only few nanoscaled
+off-stoichiometry cementite particles remain and a nanoscaled equiaxed grain
+structure with a grain size of about 20 nm was revealed. 3D-AP data clearly
+point out a strong segregation of carbon atoms along grain boundaries. The
+influence of this carbon atom segregation on the nanostructure formation is
+discussed and a scenario accounting for the nanocrystallisation during severe
+plastic deformation is proposed.",0804.4377v1
+2008-06-30,Beam Coupling Impedance Measurement and Mitigation for a TOTEM Roman Pot,"The longitudinal and transverse beam coupling impedance of the first final
+TOTEM Roman Pot unit has been measured in the laboratory with the wire method.
+For the evaluation of transverse impedance the wire position has been kept
+constant, and the insertions of the RP were moved asymmetrically. With the
+original configuration of the RP, resonances with fairly high Q values were
+observed. In order to mitigate this problem, RF-absorbing ferrite plates were
+mounted in appropriate locations. As a result, all resonances were sufficiently
+damped to meet the stringent LHC beam coupling impedance requirements.",0806.4974v1
+2008-09-02,Parametrically-stimulated recovery of a microwave signal using standing spin-wave modes of a magnetic film,"The phenomenon of storage and parametrically-stimulated recovery of a
+microwave signal in a ferrite film has been studied both experimentally and
+theoretically. The microwave signal is stored in the form of standing spin-wave
+modes existing in the film due to its finite thickness. Signal recovery is
+performed by means of frequency-selective amplification of one of these
+standing modes by double- requency parametric pumping process. The time of
+recovery, as well as the duration and magnitude of the recovered signal, depend
+on the timing and amplitudes of both the input and pumping pulses. A mean-field
+theory of the recovery process based on the competitive interaction of the
+signal-induced standing spin-wave mode and thermal magnons with the parametric
+pumping field is developed and compared to the experimental data.",0809.0395v1
+2008-10-15,Magnetic susceptibility and magnetization fluctuation measurements of mixed Gadolinium-Yttrium Iron Garnets,"We study the magnetic properties of Gadolinium-Yttrium Iron Garnet
+($\text{Gd}_{x}\text{Y}_{3-x}\text{Fe}_5\text{0}_{12}$, $x=3,1.8$) ferrite
+ceramics. The complex initial permeability is measured in the temperature range
+2 K to 295 K at frequency of 1 kHz, and in the frequency range 100 Hz to 200
+MHz at temperatures 4 K, 77 K, and 295 K. The magnetic viscosity-induced
+imaginary part of the permeability is observed at low frequencies. Measurements
+of the magnetization noise are made at 4 K. Using the fluctuation-dissipation
+theorem, we find that the observed magnetization fluctuations are consistent
+with our measurements of the low-frequency imaginary part of permeability. We
+discuss some implications for proposed precision measurements as well as other
+possible applications.",0810.2770v1
+2008-12-02,"Phase transitions in multiferroic BiFeO3 crystals, thin-layers, and ceramics: Enduring potential for a single phase, room-temperature magnetoelectric 'holy grail'","Magnetic phase transitions in multiferroic bismuth ferrite (BiFeO3) induced
+by magnetic field, epitaxial strain, and composition modification are
+considered. These transitions from a spatially modulated spin spiral state to a
+homogenous antiferromagnetic one are accompanied by the release of latent
+magnetization and a linear magnetoelectric effect that makes BiFeO3-based
+materials efficient room-temperature single phase multiferroics.",0812.0484v2
+2008-12-24,Design and optimization of one-dimensional ferrite-film based magnonic crystals,"One-dimensional magnonic crystals have been implemented as gratings of
+shallow grooves chemically etched into the surface of yttrium-iron garnet
+films. Scattering of backward volume magnetostatic spin waves from such
+structures is investigated experimentally and theoretically. Well-defined
+rejection frequency bands are observed in transmission characteristics of the
+magnonic crystals. The loss inserted by the gratings and the rejections bands
+bandwidths are studied as a function of the film thickness, the groove depth,
+the number of grooves, and the groove width. The experimental data are well
+described by a theoretical model based on the analogy of a spin-wave
+film-waveguide with a microwave transmission line. Our study shows that
+magnonic crystals with required operational characteristics can be engineered
+by adjusting these geometrical parameters.",0812.4553v1
+2009-01-23,Structural Origin of the Metal-Insulator Transition of Multiferroic BiFeO3,"We report X-ray structural studies of the metal-insulator phase transition in
+bismuth ferrite, BiFeO3, both as a function of temperature and of pressure (931
+oC at atmospheric pressure and ca. 45 GPa at ambient temperature). Based on the
+experimental results, we argue that the metallic gamma-phase is not
+rhombohedral but is instead the same cubic Pm3m structure whether obtained via
+high temperature or high pressure, that the MI transition is second order or
+very nearly so, that this is a band-type transition due to semi-metal band
+overlap in the cubic phase and not a Mott transition, and that it is primarily
+structural and not an S=5/2 to S=1/2 high-spin/low-spin electronic transition.
+Our data are compatible with the orthorhombic Pbnm structure for the beta-phase
+determined definitively by the neutron scattering study of Arnold et al .[Phys.
+Rev. Lett. 2009]; the details of this beta-phase had also been controversial,
+with a remarkable collection of five crystal classes (cubic, tetragonal,
+orthorhombic, monoclinic, and rhombohedral!) all claimed in recent
+publications.",0901.3748v2
+2009-04-02,Current-controlled dynamic magnonic crystal,"We demonstrate a current-controlled, dynamic magnonic crystal. It consists of
+a ferrite film whose internal magnetic field exhibits a periodic, cosine-like
+variation. The field modulation is created by a direct current flowing through
+an array of parallel wires placed on top of a spin-wave waveguide. A single,
+pronounced rejection band in the spin-wave transmission characteristics is
+formed due to spin-wave scattering from the inhomogeneous magnetic field. With
+increasing current the rejection band depth and its width increase strongly.
+The magnonic crystal allows a fast control of its operational characteristics
+via the applied direct current. Simulations confirm the experimental results.",0904.0332v1
+2009-09-27,Strain-induced isosymmetric phase transition in BiFeO3,"We calculate the effect of epitaxial strain on the structure and properties
+of multiferroic bismuth ferrite, BiFeO3, using first-principles density
+functional theory. We find that, while small strains cause only quantitative
+changes in behavior from the bulk material, compressive strains of greater than
+4% induce an isosymmetric phase transition accompanied by a dramatic change in
+structure. In striking contrast to the bulk rhombohedral perovskite, the highly
+strained structure has a c/a ratio of ~1.3 and five-coordinated Fe atoms. We
+predict a rotation of polarization from [111] (bulk) to nearly [001],
+accompanied by an increase in magnitude of ~50%, and a suppression of the
+magnetic ordering temperature. Intriguingly, our calculations indicate critical
+strain values at which the two phases might be expected to coexist.",0909.4979v4
+2009-09-29,First-principles study of ferroelectric domain walls in multiferroic bismuth ferrite,"We present a first-principles density functional study of the structural,
+electronic and magnetic properties of the ferroelectric domain walls in
+multiferroic BiFeO3. We find that domain walls in which the rotations of the
+oxygen octahedra do not change their phase when the polarization reorients are
+the most favorable, and of these the 109 degree domain wall centered around the
+BiO plane has the lowest energy. The 109 degree and 180 degree walls have a
+significant change in the component of their polarization perpendicular to the
+wall; the corresponding step in the electrostatic potential is consistent with
+a recent report of electrical conductivity at the domain walls. Finally, we
+show that changes in the Fe-O-Fe bond angles at the domain walls cause changes
+in the canting of the Fe magnetic moments which can enhance the local
+magnetization at the domain walls.",0909.5294v1
+2009-10-30,Charge and orbital ordering in Fe and Mn perovskite oxides far from half- doping by resonant x- ray scattering,"The emergence of superlattice periodicities at metal to insulator transitions
+in hole doped perovskite oxides responds to a rearrangement of the local atomic
+structure, and electron and spin density distribution. Originally, the ionic
+model based on a checkerboard- type atomic distribution served to describe the
+low temperature charge and orbital ordered (COO) phases arising in half- doped
+manganites. In the last years, the exploitation of resonant x- ray scattering
+(RXS) capabilities has shown the need to revisit these concepts and improve the
+picture. Yet, we have realised that COO is a more common phenomenon than
+expected that can be observed in a wide range of doping levels. Here we compare
+the experimental data recently collected by RXS on La_0.4Sr_1.6MnO_4 (x=0.60)
+and La(Pr)_1/3Sr_2/3FeO_3 (x=0.67). The first shows a COO phase similar to that
+found in the x=0.5 sample but angular peak positions vs. T denotes the
+incommensurability of superlattice reflections. Meanwhile, the analysis of the
+commensurate CO phase in the studied ferrite underlines the role of the
+structural changes also involving La(Sr) and O atoms.",0910.5788v1
+2010-02-04,Polarization transformations by a magneto-photonic layered structure in vicinity of ferromagnetic resonance,"The polarization properties of a magnetophotonic crystal at the frequencies
+located in the vicinity of ferromagnetic resonance are studied. The
+investigations are curried out taking into consideration the fact that the
+magnitude of material losses in ferrite layers at this frequency band is
+significant. The method is based on obtaining a system of ordinary differential
+equations and further analyzing the stability of solutions of this system. The
+electromagnetic properties of the structure under study are found out via the
+analysis of the eigenvalues of the transfer matrix of the structure period. On
+this basis the boundaries of the stopbands and passbands of the eigenwaves are
+determined. The frequency and angular dependences of the reflection and
+transmission coefficients are given. The angle of the rotation of the
+polarization plane and the ellipticity of the reflected and transmitted fields
+are obtained.",1002.1087v2
+2010-06-16,Sub-monolayers of carbon on alpha-iron facets: an ab-initio study,"Motivated by recent in situ studies of carbon nanotube growth from large
+transition-metal nanoparticles, we study various alpha-iron (ferrite) facets at
+different carbon concentrations using ab initio methods. The studied (110),
+(100) and (111) facets show qualitatively different behaviour when carbon
+concentration changes. In particular, adsorbed carbon atoms repel each other on
+the (110) facet, resulting in carbon dimer and graphitic material formation.
+Carbon on the (100) facet forms stable structures at concentrations of about
+0.5 monolayer and at 1.0 monolayer this facet becomes unstable due to a
+frustration of the top layer iron atoms. The stability of the (111) facet is
+weakly affected by the amount of adsorbed carbon and its stability increases
+further with respect to the (100) facet with increasing carbon concentration.
+The exchange of carbon atoms between the surface and sub-surface regions on the
+(111) facet is easier than on the other facets and the formation of carbon
+dimers is exothermic. These findings are in accordance with a recent in situ
+experimental study where the existence of graphene decorated (111) facets is
+related to increased carbon concentration.",1006.3187v1
+2010-08-17,Imaging ferroelectric domains in multiferroics using a low-energy electron microscope in the mirror operation mode,"We report on low-energy electron microscopy imaging of ferroelectric domains
+with submicron resolution. Periodic strips of 'up' and 'down'-polarized
+ferroelectric domains in bismuth ferrite -a room temperature multiferroic-
+serve as a model system to compare low-energy electron microscopy with the
+established piezoresponse force microscopy. The results confirm the possibility
+of full-field imaging of ferroelectric domains with short acquisition times by
+exploiting the sensitivity of ultraslow electrons to small variations of the
+electric potential near surfaces in the ""mirror"" operation mode.",1008.2861v1
+2010-11-08,Calculation of the substitutional fraction of ion-implanted He in an Fe target,"Ion-implantation is a useful technique to study irradiation damage in nuclear
+materials. To study He effects in nuclear fusion conditions, He is co-implanted
+with damage ions to reproduce the correct He/dpa ratios in the desired or
+available depth range. However, the short-term fate of these He ions, i.e over
+the time scales of their own collisional phase, has not been yet unequivocally
+established. Here we present an atomistic study of the short-term evolution of
+He implantation in an Fe substrate to approximate the conditions encountered in
+dual ion-implantation studies in ferritic materials. Specifically, we calculate
+the fraction of He atoms that end up in substitutional sites shortly after
+implantation, i.e. before they contribute to long-term miscrostructural
+evolution. We find that fractions of at most 3% should be expected for most
+implantation studies. In addition, we carry out an exhaustive calculation of
+interstitial He migration energy barriers in the vicinity of matrix vacancies
+and find that they vary from approximately 20 to 60 meV depending on the
+separation and orientation of the He-vacancy pair.",1011.1867v1
+2010-12-14,Scaling behavior of the spin pumping effect in ferromagnet/platinum bilayers,"We systematically measured the DC voltage V_ISH induced by spin pumping
+together with the inverse spin Hall effect in ferromagnet/platinum bilayer
+films. In all our samples, comprising ferromagnetic 3d transition metals,
+Heusler compounds, ferrite spinel oxides, and magnetic semiconductors, V_ISH
+invariably has the same polarity. V_ISH furthermore scales with the
+magnetization precession cone angle with a universal prefactor, irrespective of
+the magnetic properties, the charge carrier transport mechanism or type. These
+findings quantitatively corroborate the present theoretical understanding of
+spin pumping in combination with the inverse spin Hall effect.",1012.3017v2
+2011-02-02,Interstitial Fe-Cr alloys: Tuning of magnetism by nanoscale structural control and by implantation of nonmagnetic atoms,"Using the density functional theory, we perform a full atomic relaxation of
+the bulk ferrite with 12.5%-concentration of monoatomic interstitial Cr
+periodically located at the edges of the bcc Fe$_\alpha$ cell. We show that
+structural relaxation in such artificially engineered alloys leads to
+significant atomic displacements and results in the formation of novel highly
+stable configurations with parallel chains of octahedrically arranged Fe. The
+enhanced magnetic polarization in the low-symmetry metallic state of this type
+of alloys can be externally controlled by additional inclusion of nonmagnetic
+impurities like nitrogen. We discuss possible applications of generated
+interstitial alloys in spintronic devices and propose to consider them as a
+basis of novel durable types of stainless steels.",1102.0432v2
+2011-02-21,"The energetic and structural properties of bcc NiCu, FeCu alloys: a first-principles study","Using special quasirandom structures (SQS's), we perform first-principles
+calculations studying the metastable bcc NiCu and FeCu alloys which occur in
+Fe-Cu-Ni alloy steels as precipitated second phase. The mixing enthalpies,
+density of state, and equilibrium lattice parameters of these alloys are
+reported. The results show that quasi-chemical approach and vegard rule can
+well predict the energetic and structural properties of FeCu alloys but fail to
+yield that of NiCu. The reason rests with the difference of bond energy
+variation with composition between NiCu and FeCu alloys induced by competition
+between ferromagnetic and paramagnetic state. Furthermore, the calculated
+results show that the energetic and structural properties of these alloys can
+well explain the local composition of the corresponding precipitates in ferrite
+steels.",1102.4115v2
+2011-03-22,Magnetic Interactions in Ball-Milled Spinel Ferrites,"Spinel Fe3O4 nanoparticles have been produced through ball milling in
+methyl-alcohol (CH3OH), aiming to obtain samples with similar average particle
+sizes <d> and different interparticle interactions. Three samples having
+Fe3O4/CH3(OH) mass ratios R of 3 %, 10 % and 50 % wt. were milled for several
+hours until particle size reached a steady value (<d> ~ 7-10 nm). A detailed
+study of static and dynamic magnetic properties has been undertaken by
+measuring magnetization, ac susceptibility and M\""ossbauer data. As expected
+for small particles, the Verwey transition was not observed, but instead
+superparamagnetic (SPM) behavior was found with transition to a blocked state
+at TB ~ 10-20 K. Spin disorder of the resulting particles, independent of its
+concentration, was inferred from the decrease of saturation magnetization MS at
+low temperatures. For samples having 3% wt. of magnetic particles, dynamic ac
+susceptibility measurements show a thermally activated Arrhenius dependence of
+the blocking temperature with applied frequency. This behaviour is found to
+change as interparticle interactions begin to rule the dynamics of the system,
+yielding a spin-glass-like state at low temperatures for R = 50 wt.% sample.",1103.4390v1
+2011-07-19,Composition Dependence of Structural Parameters and Properties of Gallium Ferrite,"We show the effect of composition on structural and magnetic characteristics
+of pure phase polycrystalline Ga<2-x>Fe<x>O<3> (GFO) for compositions between
+0.8 <= x <= 1.3. X-ray analysis reveals that lattice parameters of GFO exhibit
+a linear dependence on Fe content in single phase region indicating
+manifestation of Vegard's law. Increasing Fe content of the samples also leads
+to stretching of bonds as indicated by the Raman peak shifts. Further, low
+temperature magnetic measurements show that the coercivity of the samples is
+maximum for Ga:Fe ratio of 1:1 driven by a competition between decreasing
+crystallite size and increasing magnetic anisotropy.",1107.3623v1
+2011-12-15,On the Angular Width of Diffractive Beam in Anisotropic Media,"2-D diffraction patterns arising in the far-field region were investigated
+theoretically for the case, when the plane wave with non collinear group and
+phase velocities is incident on the wide slit in opaque screen with arbitrary
+orientation. This investigation was carried out by consideration as an example
+of magnetostatic surface wave diffraction in tangentially magnetized ferrite
+slab. It was deduced the universal analytical formula, which one can use to
+calculate the angular width of diffractive beam in any 2-D anisotropic
+geometries for the waves of various nature. It was shown, that in 2-D
+anisotropic geometries this width may be not only more or less then the value
+L/D (L - wavelength of incident wave, D - length of slit), but it also may be
+equal to zero in certain conditions.",1112.3929v1
+2012-02-06,High-temperature spin-wave propagation in BiFeO3: relation to the Polomska transition,"In bismuth ferrite thin films the cycloidal spiral spin structure is
+suppressed, and as a result the spin-wave magnon branches of long wavelength
+are reduced from a dozen to one, at \omega = 19.2 cm-1 (T=4K). This spin wave
+has not been measured previously above room temperature, but in the present
+work we show via Raman spectroscopy that it is an underdamped propagating wave
+until 455 K. This has important room-temperature device implications. The data
+show that \omega(T) follows an S=5/2 Brillouin function and hence its Fe+3 ions
+are in the high-spin 5/2 state and not the low-spin S=1/2 state. The spin wave
+cannot be measured as a propagating wave above 455 K. We also suggest that
+since this temperature is coincident with the mysterious ""Polomska transition""
+(M. Polomska et al., Phys. Stat. Sol. A 23, 567, (1974)) at 458+/-5 K, that
+this may be due to overdamping.",1202.1040v1
+2012-02-15,Surface phase transitions in BiFeO3 below room temperature,"We combine a wide variety of experimental techniques to analyze two
+heretofore mysterious phase transitions in multiferroic bismuth ferrite at low
+temperature. Raman spectroscopy, resonant ultrasound spectroscopy, EPR, X-ray
+lattice constant measurements, conductivity and dielectric response, specific
+heat and pyroelectric data have been collected for two different types of
+samples: single crystals and, in order to maximize surface/volume ratio to
+enhance surface phase transition effects, BiFeO3 nanotubes were also studied.
+The transition at T=140.3K is shown to be a surface phase transition, with an
+associated sharp change in lattice parameter and charge density at the surface.
+Meanwhile, the 201K anomaly appears to signal the onset of glassy behaviour.",1202.3387v1
+2012-02-19,"Nanoscale austenite reversion through partitioning, segregation, and kinetic freezing: Example of a ductile 2 GPa Fe-Cr-C steel","Austenite reversion during tempering of a Fe-13.6Cr-0.44C (wt.%) martensite
+results in an ultrahigh strength ferritic stainless steel with excellent
+ductility. The austenite reversion mechanism is coupled to the kinetic freezing
+of carbon during low-temperature partitioning at the interfaces between
+martensite and retained austenite and to carbon segregation at
+martensite-martensite grain boundaries. An advantage of austenite reversion is
+its scalability, i.e., changing tempering time and temperature tailors the
+desired strength-ductility profiles (e.g. tempering at 400{\deg}C for 1 min.
+produces a 2 GPa ultimate tensile strength (UTS) and 14% elongation while 30
+min. at 400{\deg}C results in a UTS of ~ 1.75 GPa with an elongation of 23%).
+The austenite reversion process, carbide precipitation, and carbon segregation
+have been characterized by XRD, EBSD, TEM, and atom probe tomography (APT) in
+order to develop the structure-property relationships that control the
+material's strength and ductility.",1202.4135v1
+2012-02-28,"Gallium Substituted ""114"" YBaFe4O7: From a ferrimagnetic cluster glass to a cationic disordered spin glass","The study of the ferrites YBaFe4-xGaxO7 shows that the substitution of Ga for
+Fe in YBaFe4O7 stabilizes the hexagonal symmetry for 0.40 < x < 0.70, at the
+expense of the cubic one. Using combined measurements of a. c. and d. c.
+magnetization, we establish that Ga substitution for Fe in YBaFe4O7 leads to an
+evolution from a geometrically frustrated spin glass (for x = 0) to a cationic
+disorder induced spin glass (x = 0.70). We also find an intermediate narrow
+range of doping where the samples are clearly phase separated having small
+ferrimagnetic clusters embedded in a spin glass matrix. The origin of the
+ferrimagnetic clusters lies in the change in symmetry of the samples from cubic
+to hexagonal (and a consequent lifting of the geometrical frustration) as a
+result of Ga doping. We also show the presence of exchange bias and domain wall
+pinning in these samples. The cause of both these effects can be traced back to
+the inherent phase separation present in the samples.",1202.6166v1
+2012-07-19,Raman study of the phonon symmetries in BiFeO$_3$ single crystals,"In bismuth ferrite (BiFeO3), antiferromagnetic and ferroelectric order
+coexist at room temperature, making it of particular interest for studying
+magnetoelectric coupling. The mutual control of magnetic and electric
+properties is very useful for a wide variety of applications. This has led to
+an enormous amount of research into the properties of BiFeO$_3$. Nonetheless,
+one of the most fundamental aspects of this material, namely the symmetries of
+the lattice vibrations, remains controversial.We present a comprehensive Raman
+study of BiFeO$_3$ single crystals with the approach of monitoring the Raman
+spectra while rotating the polarization direction of the excitation laser. Our
+method results in unambiguous assignment of the phonon symmetries and explains
+the origin of the controversy in the literature. Furthermore, it provides
+access to the Raman tensor elements enabling direct comparison with theoretical
+calculations. Hence, this allows the study of symmetry breaking and coupling
+mechanisms in a wide range of complex materials and may lead to a noninvasive,
+all-optical method to determine the orientation and magnitude of the
+ferroelectric polarization.",1207.4799v1
+2012-10-03,Direct calorimetric measurements of isothermal entropy change on single crystal W-type hexaferrites at the spin reorientation transition,"We report on the magnetic field induced isothermal entropy change, \Delta
+s(Ha, T), of W-type ferrite with CoZn substitution. Entropy measurements are
+performed by direct calorimetry. Single crystals of the composition
+BaCo$_0.62$Zn$_1.38$Fe$_16$O$_27$, prepared by the flux method, are measured at
+different fixed temperatures under an applied field perpendicular and parallel
+to the c axis. At 296 K one deduces a value of K$_1$ = 8.7 \times 10^{4} J
+m$^-3$ for the first anisotropy constant, which is in good agreement with the
+literature. The spin reorientation transition temperature is estimated to take
+place between 200 and 220 K.",1210.0997v1
+2012-11-05,Exact asymptotic behavior of magnetic stripe domain arrays,"The classical problem of magnetic stripe domain behavior in films and plates
+with uniaxial magnetic anisotropy is treated. Exact analytical results are
+derived for the stripe domain widths as function of applied perpendicular
+field, $H$, in the regime where the domain period becomes large. The stripe
+period diverges as $(H_c-H)^{-1/2}$, where $H_c$ is the critical (infinite
+period) field, an exact result confirming a previous conjecture. The
+magnetization approaches saturation as $(H_c-H)^{1/2}$, a behavior which
+compares excellently with experimental data obtained for a $4 \mu$m thick
+ferrite garnet film. The exact analytical solution provides a new basis for
+precise characterization of uniaxial magnetic films and plates, illustrated by
+a simple way to measure the domain wall energy. The mathematical approach is
+applicable for similar analysis of a wide class of systems with competing
+interactions where a stripe domain phase is formed.",1211.1366v1
+2013-01-11,Spin-filtering efficiency of ferrimagnetic spinels CoFe2O4 and NiFe2O4,"We assess the potential of the ferrimagnetic spinel ferrites CoFe2O4 and
+NiFe2O4 to act as spin filtering barriers in magnetic tunnel junctions. Our
+study is based on the electronic structure calculated by means of
+first-principles density functional theory within different approximations for
+the exchange correlation energy. We show that, in agreement with previous
+calculations, the densities of states suggest a lower tunneling barrier for
+minority spin electrons, and thus a negative spin-filter effect. However, a
+more detailed analysis based on the complex band-structure reveals that both
+signs for the spin-filtering efficiency are possible, depending on the band
+alignment between the electrode and the barrier materials and depending on the
+specific wave-function symmetry of the relevant bands within the electrode.",1301.2541v1
+2013-02-12,Anomalous Surface Segregation Profiles in Ferritic FeCr Stainless Steel,"The iron-chromium alloy and its derivatives are widely used for their
+remarkable resistance to corrosion, which only occurs in a narrow concentration
+range around 9 to 13 atomic percent chromium. Although known to be due to
+chromium enrichment of a few atoms thick layer at the surfaces, the
+understanding of its complex atomistic origin has been a remaining challenge.
+We report an investigation of the thermodynamics of such surfaces at the atomic
+scale by means of Monte Carlo simulations. We use a Hamiltonian which provides
+a parameterization of previous ab initio results and successfully describes the
+alloy's unusual thermodynamics. We report a strong enrichment in Cr of the
+surfaces for low bulk concentrations, with a narrow optimum around 12 atomic
+percent chromium, beyond which the surface composition decreases drastically.
+This behavior is explained by a synergy between (i) the complex phase
+separation in the bulk alloy, (ii) local phase transitions that tune the layers
+closest to the surface to an iron-rich state and inhibit the bulk phase
+separation in this region, and (iii) its compensation by a strong and
+non-linear enrichment in Cr of the next few layers. Implications with respect
+to the design of prospective nanomaterials are briefly discussed.",1302.2838v1
+2013-02-16,Room Temperature Nanoscale Ferroelectricity in Magnetoelectric GaFeO3 Epitaxial Thin Films,"We demonstrate room temperature ferroelectricity in the epitaxial thin films
+of magnetoelectric GaFeO3. Piezo-force measurements show a 180o phase shift of
+piezoresponse upon switching the electric field indicating nanoscale
+ferroelectricity in epitaxial thin films of gallium ferrite. Further,
+temperature dependent impedance analysis with and without the presence of an
+external magnetic field clearly reveals a pronounced magneto-dielectric effect
+across the magnetic transition temperature. In addition, our first principles
+calculations show that Fe ions are not only responsible for ferrimagnetism as
+observed earlier, but also give rise to the observed ferroelectricity, making
+GFO an unique single phase multiferroic.",1302.3983v2
+2013-04-04,Surface parameters of ferritic iron-rich Fe-Cr alloy,"Using first-principles density functional theory in the implementation of the
+exact muffin-tin orbitals method and the coherent potential approximation, we
+studied the surface energy and the surface stress of the thermodynamically most
+stable surface facet (100) of the homogeneous disordered body-centred cubic
+iron-chromium system in the concentration interval up to 20 at.% Cr. For the
+low-index surface facets of Fe and Cr, the surface energy of Cr is slightly
+larger than the one of Fe, while the surface stress of Cr is considerably
+smaller than the one of Fe. We find that Cr addition to Fe generally increases
+the surface energy of the Fe-Cr alloy, however, an increase of the bulk amount
+of Cr also increases the surface stress. As a result of this unexpected trend,
+the (100) surface of Fe-Cr becomes more stable against reconstruction with
+increasing Cr concentration. We show that the observed trends are of magnetic
+origin. In addition to the homogeneous alloy case, we also investigated the
+impact of surface segregation on both surface parameters.",1304.1278v2
+2013-07-29,Simple concentration-dependent pair interaction model for large-scale simulations of Fe-Cr alloys,"This work is motivated by the need for large-scale simulations to extract
+physical information on the iron-chromium system that is a binary model alloy
+for ferritic steels used or proposed in many nuclear applications. From
+first-principles calculations and the experimental critical temperature we
+build a new energetic rigid lattice model based on pair interactions with
+concentration and temperature dependence. Density functional theory
+calculations in both norm-conserving and projector augmented-wave approaches
+have been performed. A thorough comparison of these two different ab initio
+techniques leads to a robust parametrization of the Fe-Cr Hamiltonian.
+Mean-field approximations and Monte Carlo calculations are then used to account
+for temperature effects. The predictions of the model are in agreement with the
+most recent phase diagram at all temperatures and compositions. The solubility
+of Cr in Fe below 700 K remains in the range of about 6 to 12%. It reproduces
+the transition between the ordering and demixing tendency and the spinodal
+decomposition limits are also in agreement with the values given in the
+literature.",1307.7561v1
+2013-11-05,"Diffusion behavior in diluted ($Fe,Cr$) alloys: An environment for H diffusion in ferritic steels","Impurity diffusion coefficients are entirely obtained from a low cost
+classical molecular statics technique (CMST). In particular, we show how the
+CMST is appropriate in order to describe the impurity diffusion behavior
+mediated by a vacancy mechanism. In the context of the five-frequency model,
+CMST allows to calculate all the microscopic parameters, namely: the free
+energy of vacancy formation, the vacancy-solute binding energy and the involved
+jump frequencies, from them, we obtain the macroscopic transport magnitudes
+such as: correlation factor, solvent-enhancement factor, Onsager and diffusion
+coefficients. Also, we report for the first time the behavior of diffusion
+coefficients for the solute-vacancy paired specie. We perform our calculations
+in diluted NiAl and AlU f.c.c. alloys. Our results are in perfect agreement
+with available experimental data for both systems and predict that for NiAl the
+solute diffuses through a vacancy interchange mechanism, while for the AlU
+system, a vacancy drag mechanism occurs.",1311.1177v1
+2013-12-09,Giant Photogalvanic Effect in Metamaterials Containing Non-Centrosymmetric Plasmonic Nanoparticles,"Photoelectric properties of metamaterials containing non-centrosymmetric,
+similarly oriented metallic nanoparticles embedded in a homogeneous
+semiconductor matrix are theoretically studied. Due to the asymmetric shape of
+the nanoparticle boundary, photoelectron emission acquires a preferred
+direction, resulting in a photocurrent flow in that direction when
+nanoparticles are uniformly illuminated by a homogeneous plane wave. This
+effect is a direct analogy of the photogalvanic (or bulk photovoltaic) effect
+known to exist in media with non-centrosymmetric crystal structure, such as
+doped lithium niobate or bismuth ferrite, but is several orders of magnitude
+stronger. Termed the giant plasmonic photogalvanic effect, the reported
+phenomenon is valuable for characterizing photoemission and photoconductive
+properties of plasmonic nanostructures, and can find many uses for
+photodetection and photovoltaic applications.",1312.2428v2
+2014-01-20,Determining polarizability tensors for an arbitrary small electromagnetic scatterer,"In this paper, we present a method to retrieve tensor polarizabilities of
+general bi-anisotropic particles from their far-field responses to plane-wave
+illuminations. The necessary number of probing excitations and the directions
+where the scattered fields need to be calculated or measured have been found.
+When implemented numerically, the method does not require any spherical
+harmonic expansion nor direct calculation of dipole moments, but only
+calculations of co- and cross-polarized scattering cross sections for a number
+of plane-wave excitations. With this simple approach, the polarizabilities can
+be found also from experimentally measured cross sections. The method is
+exemplified considering two bi-anisotropic particles, a reciprocal omega
+particle and a non-reciprocal particle containing a ferrite inclusion coupled
+to metal strips.",1401.4930v1
+2014-02-14,Scattering Experiments with Microwave Billiards at an Exceptional Point under Broken Time Reversal Invariance,"Scattering experiments with microwave cavities were performed and the effects
+of broken time-reversal invariance (TRI), induced by means of a magnetized
+ferrite placed inside the cavity, on an isolated doublet of nearly degenerate
+resonances were investigated. All elements of the effective Hamiltonian of this
+two-level system were extracted. As a function of two experimental parameters,
+the doublet and also the associated eigenvectors could be tuned to coalesce at
+a so-called exceptional point (EP). The behavior of the eigenvalues and
+eigenvectors when encircling the EP in parameter space was studied, including
+the geometric amplitude that builds up in the case of broken TRI. A
+one-dimensional subspace of parameters was found where the differences of the
+eigenvalues are either real or purely imaginary. There, the Hamiltonians were
+found PT-invariant under the combined operation of parity (P) and time reversal
+(T) in a generalized sense. The EP is the point of transition between both
+regions. There a spontaneous breaking of PT occurs.",1402.3537v1
+2014-04-06,Preparation and Characterization of Nano-particle Substituted Barium Hexaferrite,"High density magnetic recording requires high coercivity magnetic media and
+small particle size. Barium hexaferrite has been considered as a leading
+candidate material because of its chemical stability, fairly large crystal
+anisotropy and suitable magnetic characteristics. In this work, we present the
+preparation of the hexagonal ferrite BaFe12O19 and one of its derivative; the
+Zn-Sn substituted hexaferrite by the chemical co-precipitation method. The main
+advantage of this method on the conventional glass-ceramic one, resides in
+providing a small enough particle size for magnetic recording. We demonstrate
+using the X-ray diffraction patterns that the particle size decreases when
+substituting the hexaferrite by the Zn-Sn combination. This may improve the
+magnetic properties of the hexaferrite as a medium for HD magnetic recording",1404.1573v1
+2014-04-22,"Analytic Modeling, Simulation and Interpretation of Broadband Beam Coupling Impedance Bench Measurements","In the first part of the paper a generalized theoretical approach towards
+beam coupling impedances and stretched-wire measurements is introduced. Applied
+to a circular symmetric setup, this approach allows to estimate the systematic
+measurement error due to the presence of the wire. Further, the interaction of
+the beam or the TEM wave, respectively, with dispersive material such as
+ferrite is discussed. The dependence of the obtained impedances on the
+relativistic velocity $\beta$ is investigated and found as material property
+dependent. The conversion formulas for the TEM scattering parameters from
+measurements to impedances are compared with each other and the analytical
+impedance solution. In the second part of the paper the measurements are
+compared to numerical simulations of wakefields and scattering parameters. In
+practice, the measurements have been performed for the circularly symmetric
+example setup. The optimization of the measurement process is discussed. The
+paper concludes with a summary of systematic and statistic error sources for
+impedance bench measurements and their diminishment strategy.",1404.5593v1
+2014-07-21,Unidirectional magnetoelectric-field multiresonant tunneling,"Unidirectional multi-resonant tunneling of the magneto-electric (ME)-field
+excitations through a sub wavelength (regarding the scales of regular
+electromagnetic radiation) vacuum or isotropic-dielectric regions has been
+observed in two-port microwave structures having a quasi-2D ferrite disk with
+magnetic-dipolar-mode (MDM) oscillations. The excitations manifest themselves
+as the Fano-resonance peaks in the scattering-matrix parameters at the
+stationary states of the MDM spectrum. The ME near-field excitations are quasi
+magnetostatic fields with non-zero helicity parameter. Topological-phase
+properties of ME fields are determined by edge chiral currents of MDM
+oscillations. We show that while for a given direction of a bias magnetic field
+(in other words, for a given direction of time), the ME-field excitations are
+considered as forward tunneling processes, in the opposite direction of a bias
+magnetic field (the opposite direction of time), there are backward tunneling
+processes. Unidirectional ME-field resonant tunneling is observed due to
+distinguishable topology of the forward and backward ME-field excitations. We
+establish a close connection between the Fano-resonance unidirectional
+tunneling and topology of ME fields in different microwave structures.",1407.5522v1
+2014-08-01,Effect of the techniqie of drawing with shear on the structure and the properties of low-carbon wires,"The technology of drawing with shear is developed. It allows increasing
+technological plasticity of low carbon steel without heat treatment. It is
+found that the use of experimental technology can improve mechanical properties
+of wire samples with the diameter reduced during drawing: the relative
+reduction of the wire decreases slightly and remains at high level compared
+with the classical technology, where the relative reduction in the course of
+drawing drops more than twice. It is shown that the use of experimental
+technology allows varying the size of a ferrite grain (increase or decrease)
+compared with the classical technology, where increasing of deformation degree
+results in grain reduction. Furthermore, the experimental technology allows
+reducing the number of pores in a wire of small diameter. To prevent heating of
+the wire and the drawing dies, it is proposed to use experimental drawing
+through two experimental dies with shear separated by an ordinary die. As a
+result, the workability of the process will be enhanced and the efforts of
+drawing will be reduced.",1408.0125v1
+2014-08-07,Deviations from cooperative growth mode during eutectoid transformation: insights from phase-field approach,"The non-cooperative eutectoid transformation relies on the presence of
+pre-existing cementite particles in the parent austenitic phase and yields a
+product, popularly known as the divorced eutectoid. In isothermal conditions,
+two of the important parameters, which influence the transformation mechanism
+and determine the final morphology are undercooling (below A1 temperature) and
+inter-particle spacing. Although, the criteria which governs the morphological
+transition from lamellar to divorced is experimentally well established,
+numerical studies that give a detailed exposition of the non-cooperative
+transformation mechanism, have not been reported extensively. In the present
+work, we employ a multiphase-field model, that uses the thermodynamic
+information from the CALPHAD database, to numerically simulate the pulling-away
+of the advancing ferrite-austenite interface from cementite, which results in a
+transition from lamellar to divorced eutectoid morphology in Fe-C alloy. We
+also identify the onset of a concurrent growth and coarsening regime at small
+inter-particle spacing and low undercooling. We analyze the simulation results
+to unravel the essential physics behind this complex spacial and temporal
+evolution pathway and amend the existing criteria by constructing a
+Lamellar-Divorced-Coarsening (LDC) map.",1408.1571v1
+2014-08-14,Role of magnetic degrees of freedom in a scenario of phase transformations in steel,"The diversity of mesostructures formed in steel at cooling from a
+high-temperature austenite (""gamma"") phase is determined by the interplay of
+shear reconstructions of crystal lattice and diffusion of carbon. Combining
+first-principles calculations with large-scale phase-field simulations we
+demonstrate a decisive role of magnetic degrees of freedom in the formation of
+energy relief along the Bain path of ""gamma""-""alpha"" transformation and, thus,
+in this interplay. We show that there is the main factor, namely, the magnetic
+state of iron and its evolution with temperature which controls the change in
+character of the transformation. Based on the computational results we propose
+a simple model which reproduces, in good agreement with experiment, the most
+important curves of the phase transformation in Fe-C, namely, the lines
+relevant to a start of ferrite, bainite, and martensite transformations.
+Phase-field simulations within the model describe qualitatively typical
+patterns at these transformations.",1408.3275v2
+2014-09-05,Theoretical assessment of boron incorporation in nickel ferrite under conditions of operating nuclear pressurized water reactors (PWRs),"A serious concern in the safety and economy of a pressurized water nuclear
+reactor is related to the accumulation of boron inside the metal oxide (mostly
+NiFe${}_{2}$O${}_{4}$ spinel) deposits on the upper regions of the fuel rods.
+Boron, being a potent neutron absorber, can alter the neutron flux causing
+anomalous shifts and fluctuations in the power output of the reactor core. This
+phenomenon reduces the operational flexibility of the plant and may force the
+down-rating of the reactor. In this work an innovative approach is used to
+combine first-principles calculations with thermodynamic data to evaluate the
+possibility of B incorporation into the crystal structure of
+NiFe${}_{2}$O${}_{4}$, under conditions typical to operating nuclear
+pressurized water nuclear reactors. Analyses of temperature and pH dependence
+of the defect formation energies indicate that B can accumulate in
+NiFe${}_{2}$O${}_{4}$ as an interstitial impurity and may therefore be a major
+contributor to the anomalous axial power shift observed in nuclear reactors.
+This computational approach is quite general and applicable to a large variety
+of solids in equilibrium with aqueous solutions.",1409.1811v1
+2014-10-29,Simultaneous Multi-Harmonic Imaging of Nanoparticles in Tissues for Increased Selectivity,"We investigate the use of Bismuth Ferrite (BFO) nanoparticles for tumor
+tissue labelling in combination with infrared multi-photon excitation at 1250
+nm. We report the efficient and simultaneous generation of second and third
+harmonic by the nanoparticles. On this basis, we set up a novel imaging
+protocol based on the co-localization of the two harmonic signals and
+demonstrate its benefits in terms of increased selectivity against endogenous
+background sources in tissue samples. Finally, we discuss the use of BFO
+nanoparticles as mapping reference structures for correlative light-electron
+microscopy.",1410.7969v2
+2014-11-09,Gaussian Beam Transmission through a Gyrotropic-Nihility Finely-Stratified Structure,"The three-dimensional Gaussian beam transmission through a
+ferrite-semiconductor finely-stratified structure being under an action of an
+external static magnetic field in the Faraday geometry is considered. The beam
+field is represented by an angular continuous spectrum of plane waves. In the
+long-wavelength limit, the studied structure is described as a
+gyroelectromagnetic medium defined by the effective permittivity and effective
+permeability tensors. The investigations are carried out in the frequency band
+where the real parts of the on-diagonal elements of both effective permittivity
+and effective permeability tensors are close to zero while the off-diagonal
+ones are non-zero. In this frequency band the studied structure is referred to
+a gyrotropic-nihility medium. It is found out that a Gaussian beam keeps its
+parameters unchanged (beam width and shape) when passing through the layer of
+such a medium except of a portion of the absorbed energy.",1411.2233v2
+2015-02-01,Magnetoelectric-field helicities and reactive power flows,"The dual symmetry between the electric and magnetic fields underlies
+Maxwell's electrodynamics. Due to this symmetry one can describe topological
+properties of an electromagnetic field in free space and obtain the
+conservation law of optical (electromagnetic) helicity. What kind of the field
+helicity one can expect to see when the electromagnetic-field symmetry is
+broken? The near fields originated from small ferrite particles with magnetic
+dipolar mode (MDM) oscillations are the fields with the electric and magnetic
+components, but with broken dual (electric-magnetic) symmetry. These fields,
+called magnetoelectric (ME) fields, have topological properties different from
+such properties of electromagnetic fields. The helicity states of ME fields are
+topologically protected quantum like states. In this paper, we study the
+helicity properties of ME fields. We analyze conservation laws of the ME-field
+helicity and show that the helicity density is related to an imaginary part of
+the complex power flow density. We show also that the helicity of ME fields can
+be a complex value.",1502.00220v1
+2015-02-04,"Novel microwave near-field sensors for material characterization, biology, and nanotechnology","The wide range of interesting electromagnetic behavior of contemporary
+materials requires that experimentalists working in this field master many
+diverse measurement techniques and have a broad understanding of condensed
+matter physics and biophysics. Measurement of the electromagnetic response of
+materials at microwave frequencies is important for both fundamental and
+practical reasons. In this paper, we propose a novel near-field microwave
+sensor with application to material characterization, biology, and
+nanotechnology. The sensor is based on a subwavelength ferrite-disk resonator
+with magnetic-dipolar-mode (MDM) oscillations. Strong energy concentration and
+unique topological structures of the near fields originated from the MDM
+resonators allow effective measuring material parameters in microwaves, both
+for ordinary structures and objects with chiral properties.",1502.01121v1
+2015-03-25,Study of helium irradiation induced hardening in MNHS steel,"A recently developed reduced activation ferritic/martensitic steel MNHS was
+irradiated with 200keV He ions to a fluence of 1E21ions/m^2 at 450 celsius
+degree and 1E20ions/m^2 at 300 celsius degree and 450 celsius degree,
+respectively. The irradiation hardening of the steel was investigated by
+nanoindentation measurements combined with transmission electron microscopy
+(TEM) analysis. Dispersed barrier-hardening (DBH) model was applied to predict
+the hardness increments based on TEM analysis. The predicted hardness
+increments are consistent with the values obtained by nanoindentation tests. It
+is found that dislocation loops and He bubbles are hard barriers against
+dislocation motion and they are the main contributions to He
+irradiation-induced hardening of MNHS steel. The obstacle strength of He
+bubbles is stronger than the obstacle strength of dislocation loops.",1503.08088v1
+2015-04-07,Impedance Measurements of the Extraction Kicker System for the Rapid Cycling Synchrotron of China Spallation Neutron Source,"The fast extraction kicker system is one of the most important accelerator
+components, whose inner structure will be the main source of the impedance in
+the RCS. It is necessary to understand the kicker impedance before its
+installation into the tunnel. The conventional and improved wire methods are
+employed for the benchmarking impedance measurement results. The simulation and
+measurements confirm that the window-frame ferrite geometry and the end plate
+are the important structures causing the coupling impedance. The total
+impedance of the eight modules systems is determined by the scaling law from
+the measurement and the impedance measurement of the kicker system is
+summarized.",1504.01500v1
+2015-04-15,Acoustic study for dynamical molecular-spin state without undergoing magnetic phase transition in spin-frustrated ZnFe$_2$O$_4$,"Ultrasound velocity measurements were performed on a single crystal of
+spin-frustrated ferrite spinel ZnFe$_2$O$_4$ from 300 K down to 2 K. In this
+cubic crystal, all the symmetrically-independent elastic moduli exhibit
+softening with a characteristic minimum with decreasing temperature below
+$\sim$100 K. This elastic anomaly suggests a coupling between dynamical lattice
+deformations and molecular-spin excitations. In contrast, the elastic
+anomalies, normally driven by the magnetostructural phase transition and its
+precursor, are absent in ZnFe$_2$O$_4$, suggesting that the spin-lattice
+coupling cannot play a role in relieving frustration within this compound. The
+present study infers that, for ZnFe$_2$O$_4$, the dynamical molecular-spin
+state evolves at low temperatures without undergoing precursor spin-lattice
+fluctuations and spin-lattice ordering. It is expected that ZnFe$_2$O$_4$
+provides the unique dynamical spin-lattice liquid-like system, where not only
+the spin molecules but also the cubic lattice fluctuate spatially and
+temporally.",1504.03792v3
+2015-05-15,Linear roto-antiferromagnetic effect in multiferroics: physical manifestations,"Using the theory of symmetry and the microscopic model we predicted the
+possibility of a linear roto-antiferromagnetic effect in the perovskites with
+structural antiferrodistortive and antiferromagnetic long-range ordering and
+found the necessary conditions of its occurrence. The main physical
+manifestations of this effect are the smearing of the antiferromagnetic
+transition and the jump of the specific heat near it. In the absence of
+external fields linear roto-antiferromagnetic coupling can induce a weak
+antiferromagnetic ordering above the Neel temperature, but below the
+temperature of antiferrodistortive transition. Therefore, there is the
+possibility of observing weak antiferromagnetism in multiferroics such as
+bismuth ferrite (BiFeO3) at temperatures T>TN, for which the Neel temperature
+TN is about 645 K, and the antiferrodistortive transition temperature is about
+1200 K. By quantitative comparison with experiment we made estimations of the
+linear roto-antiferromagnetic effect in the solid solutions of multiferroic
+Bi1-xRxFeO3 (R=La, Nd).",1505.04136v1
+2015-05-24,"Structural Properties, Impedance Spectroscopy and Dielectric Spin Relaxation of Ni-Zn Ferrite Synthesized by Double Sintering Technique","Structural properties, impedance, dielectric and electric modulus spectra
+have been used to investigate the sintering temperature (Ts) effect on the
+single phase cubic spinel Ni0.6Zn0.4Fe2O4 (NZFO) ceramics synthesized by
+standard ceramic technique. Enhancement of dielectric constants is observed
+with increasing Ts. The collective contribution of n-type and p-type carriers
+yields a clear peak in notable unusual dielectric behavior is successfully
+explained by the Rezlescu model. The non-Debye type long range dielectric
+relaxation phenomena is explained by electric modulus formalism. Fast response
+of the grain boundaries of the sample sintered at lower Ts sample leading to
+small dielectric spin relaxation time, t (several nanoseconds) have been
+determined using electric modulus spectra for the samples sintered at different
+Ts. Two clear semicircles in impedance Cole-Cole plot have also been
+successfully explained by employing two parallel RC equivalent circuits in
+series configuration taking into account no electrode contribution. Such a long
+relaxation time in NZFO ceramics could suitably be used in nanoscale spintronic
+devices.",1505.06438v2
+2015-06-01,Calculating the 3D magnetic field of ITER for European TBM studies,"The magnetic perturbation due to the ferromagnetic test blanket modules
+(TBMs) may deteriorate fast ion confinement in ITER. This effect must be
+quantified by numerical studies in 3D. We have implemented a combined finite
+element method (FEM) -- Biot-Savart law integrator method (BSLIM) to calculate
+the ITER 3D magnetic field and vector potential in detail. Unavoidable geometry
+simplifications changed the mass of the TBMs and ferritic inserts (FIs) up to
+26%. This has been compensated for by modifying the nonlinear ferromagnetic
+material properties accordingly. Despite the simplifications, the computation
+geometry and the calculated fields are highly detailed. The combination of
+careful FEM mesh design and using BSLIM enables the use of the fields
+unsmoothed for particle orbit-following simulations. The magnetic field was
+found to agree with earlier calculations and revealed finer details. The vector
+potential is intended to serve as input for plasma shielding calculations.",1506.00659v1
+2015-06-16,Parametric excitation of surface magnetostatic modes in an axially magnetized elliptic cylinder under longitudinal pumping,"A rigorous analytical theory of parametric excitation under the longitudinal
+pumping has been developed for the surface magnetostatic modes of a long
+elliptic ferrite cylinder magnetized along its axis with regard for the
+boundary conditions at the surface of the cylinder.It is shown that a pair of
+frequency-degenerated counter-propagating surface modes at half the pumping
+frequency can be parametrically excited, and the expressions for the
+corresponding parametric excitation threshold have been derived. The threshold
+demonstrates a strong dependence on the mode number and elliptic cylinder's
+aspect ratio and tends from above for the large aspect ratio to the value
+deduced on the basis of the plane-wave analysis.The simple analytical relation
+between the ratio of axes of the high-frequency magnetization polarization
+ellipse of excited surface magnetostatic oscillations and the parametric
+excitation threshold is obtained, discussed, and graphically illustrated.",1506.04968v1
+2015-07-07,Fast and rewritable colloidal assembly via field synchronized particle swapping,"We report a technique to realize reconfigurable colloidal crystals by using
+the controlled motion of particle defects above an externally modulated
+magnetic substrate. The transport of particles is induced by applying a uniform
+rotating magnetic field to a ferrite garnet film characterized by a periodic
+lattice of magnetic bubbles. For filling factor larger than one colloid per
+bubble domain, the particle current arises from propagating defects where
+particles synchronously exchange their position when passing from one occupied
+domain to the next. The amplitude of an applied alternating magnetic field can
+be used to displace the excess particles via a swapping mechanism, or to
+mobilize the entire colloidal system at a predefined speed.",1507.01964v1
+2015-08-24,First-principles materials design of high-performing bulk photovoltaics with the LiNbO$_3$ structure,"The bulk photovoltaic effect is a long-known but poorly understood
+phenomenon. Recently, however, the multiferroic bismuth ferrite has been
+observed to produce strong photovoltaic response to visible light, suggesting
+that the effect has been underexploited as well. Here we present three polar
+oxides in the LiNbO$_3$ structure that we predict to have band gaps in the 1-2
+eV range and very high bulk photovoltaic response: PbNiO$_3$,
+Mg$_{1/2}$Zn$_{1/2}$PbO$_3$, and LiBiO$_3$. All three have band gaps determined
+by cations with $d^{10}s^0$ electronic configurations, leading to conduction
+bands composed of cation $s$-orbitals and O $p$-orbitals. This both
+dramatically lowers the band gap and increases the bulk photovoltaic response
+by as much as an order of magnitude over previous materials, demonstrating the
+potential for high-performing bulk photovoltaics.",1508.05874v1
+2015-10-19,Ferroelectric polarization switching with a remarkably high activation-energy in orthorhombic GaFeO3 thin films,"Orthorhombic GaFeO3 (o-GFO) with the polar Pna21 space group is a prominent
+ferrite by virtue of its piezoelectricity and ferrimagnetism, coupled with
+magneto-electric effects. Herein, we unequivocally demonstrate a large
+ferroelectric remanent polarization in undoped o-GFO thin films by adopting
+either a hexagonal strontium titanate (STO) or a cubic yttrium-stabilized
+zirconia (YSZ) substrate. The polarization-electric-field hysteresis curves of
+the polar c-axis-grown o-GFO film on a SrTiO3/STO substrate show the net
+switching polarization of ~35 {\mu}C/cm2 with an unusually high coercive field
+of +-1400 kV/cm at room temperature. The PUND measurement also demonstrates the
+switching polarization of ~26 {\mu}C/cm2. The activation energy for the
+polarization switching, as obtained by density-functional theory calculations,
+is remarkably high, 1.05 eV per formula unit. This high value accounts for the
+observed stability of the polar Pna21 phase over a wide range of temperature up
+to 1368 K.",1510.05359v1
+2015-11-24,In situ resonant photoemission and X-ray absorption study of the BiFeO3 thin film,"Multiferroic bismuth ferrite (BiFeO3) thin films were prepared by pulsed
+laser deposition (PLD) technique. Electronic structures of the film have been
+studied by in situ photoemission spectroscopy (PES) and x-ray absorption
+spectroscopy (XAS). Both the Fe 2p PES and XAS spectra show that Fe ion is
+formally in +3 valence state. The Fe 2p and O K edge XAS spectra indicate that
+the oxygen octahedral crystal ligand field splits the unoccupied Fe 3d state to
+t2g and eg states. Valence band Fe 2p-3d resonant photoemission results
+indicate that hybridization between Fe 3d and O 2p plays important role in the
+multiferroic BiFeO3 thin films.",1511.07747v1
+2016-02-19,Study of Aqueous Dispersions of Magnetic Nanoparticles by Magnetic and Rheological Measurements,"The observed magnetic tunability of light transmission through a ferrofluid
+can be effectively understood in terms of the inter-particle interaction that
+can be estimated from the magnetic and rheological properties of these fluids.
+The present study reports complementary magnetic and rheological measurements
+of aqueous dispersions of ferrite nanoparticles and a commercial ferrofluid.
+The room temperature magnetization measured in a SQUID magnetometer up to
+fields of 1 to 2 Tesla showed superparamagnetic behaviour of the particles and
+the dispersion with the background signal of the liquid showing a diamagnetic
+behaviour. The room temperature rheological behaviour in zero magnetic field of
+the fluids was investigated by measuring the viscosity as a function of shear
+rate from 1-100 s-1. The particle size and the nature of the carrier liquid
+determine the viscosity and is expected to have an effect on the inter-particle
+interaction.",1602.06015v1
+2016-04-24,Optomagnonics in Magnetic Solids,"Coherent conversion of photons to magnons, and back, provides a natural
+mechanism for rapid control of interactions between stationary spins with long
+coherence times and high-speed photons. Despite the large frequency difference
+between optical photons and magnons, coherent conversion can be achieved
+through a three-particle interaction between one magnon and two photons whose
+frequency difference is resonant with the magnon frequency, as in optomechanics
+with two photons and a phonon. The large spin density of a transparent
+ferromagnetic insulator (such as the ferrite yttrium iron garnet) in an optical
+cavity provides an intrinsic photon-magnon coupling strength that we calculate
+to exceed reported optomechanical couplings. A large cavity photon number and
+properly selected cavity detuning produce a predicted effective coupling
+strength sufficient for observing electromagnetically induced transparency and
+the Purcell effect, and even to reach the ultra-strong coupling regime.",1604.07052v2
+2016-06-06,Band gap tuning and orbital mediated electron phonon coupling in $HoFe_{1-x}Cr_xO_3$,"We report on the evidenced orbital mediated electron phonon coupling and band
+gap tuning in HoFe1-xCrxO3 compounds. From the room temperature Raman
+scattering, it is apparent that the electron-phonon coupling is sensitive to
+the presence of both the Fe and Cr at the B-site. Essentially, an Ag like local
+oxygen breathing mode is activated due to the charge transfer between Fe3+ -
+Cr3+ at around 670 cm-1, this observation is explained on the basis of
+Franck-Condon (FC) mechanism. Optical absorption studies infer that there
+exists a direct band gap in the HoFe1-xCrxO3 compounds. Decrease in band gap
+until x = 0.5 is ascribed to the broadening of the oxygen p orbitals as a
+result of the induced spin disorder due to Fe3+ and Cr3+ at B site. In
+contrast, the increase in band gap above x = 0.5 is explained on the basis of
+the reduction in the available unoccupied d - orbitals of Fe3+ at the
+conduction band. We believe that above results would be helpful for the
+development of the optoelectronic devices based on the ortho-ferrites.",1606.01698v1
+2016-06-18,Magnetization reversal in mixed ferrite-chromite perovskites with non magnetic cation on the A-site,"In this work, we have performed Monte Carlo simulations in a classical model
+for RFe$_{1-x}$Cr$_x$O$_3$ with R=Y and Lu, comparing the numerical simulations
+with experiments and mean field calculations. In the analyzed compounds, the
+antisymmetric exchange or Dzyaloshinskii-Moriya (DM) interaction induced a weak
+ferromagnetism due to a canting of the antiferromagnetically ordered spins.
+This model is able to reproduce the magnetization reversal (MR) observed
+experimentally in a field cooling process for intermediate $x$ values and the
+dependence with $x$ of the critical temperatures. We also analyzed the
+conditions for the existence of MR in terms of the strength of DM interactions
+between Fe$^{3+}$ and Cr$^{3+}$ ions with the x values variations.",1606.05782v1
+2016-06-18,Enhanced diffusion and anomalous transport of magnetic colloids driven above a two-state flashing potential,"We combine experiment and theory to investigate the diffusive and
+subdiffusive dynamics of paramagnetic colloids driven above a two-state
+flashing potential. The magnetic potential was realized by periodically
+modulating the stray field of a magnetic bubble lattice in a uniaxial ferrite
+garnet film. At large amplitudes of the driving field, the dynamics of
+particles resembles an ordinary random walk with a frequency-dependent
+diffusion coefficient. However, subdiffusive and oscillatory dynamics at short
+time scales is observed when decreasing the amplitude. We present a persistent
+random walk model to elucidate the underlying mechanism of motion, and perform
+numerical simulations to demonstrate that the anomalous motion originates from
+the dynamic disorder in the structure of the magnetic lattice, induced by
+slightly irregular shape of bubbles.",1606.05783v1
+2016-07-19,Synthesis of strontium ferrite/iron oxide exchange coupled nano-powders with improved energy product for rare earth free permanent magnet applications,"We present a simple, scalable synthesis route for producing exchange coupled
+soft/hard magnetic composite powder that outperforms pure soft and hard phase
+constituents. Importantly, the composites is iron oxide based (SrFe12O19 and
+Fe3O4) and contain no rare earth or precious metal. The two step synthesis
+process consists of first precipitating, an Iron oxide/hydroxide precursor
+directly on top of SrFe12O19 nano-flakes, ensuring a very fine degree of mixing
+between the hard and the soft magnetic phases. We then use a second step that
+serves to reduce the precursor to create the proper soft magnetic phase and
+create the intimate interface necessary for exchange coupling. We establish a
+clear processing window; at temperatures below this window the desired soft
+phase is not produced, while higher temperatures result in deleterious reaction
+at the soft/hard phase interfaces, causing an improper ratio of soft to hard
+phases. Improvements of Mr, Ms, and (BH)max are 42%, 29% and 37% respectively
+in the SrFe12O19/Fe3O4 composite compared to pure hard phase (SrFe12O19). We
+provide evidence of coupling (exchange spring behavior) with hysteresis curves,
+first order reversal curve (FORC) analysis and recoil measurements.",1607.05689v1
+2016-09-14,Piezo-generated charge mapping revealed through Direct Piezoelectric Force Microscopy,"While piezoelectrics and ferroelectrics are playing a key role in many
+everyday applications, there are still a number of open questions related to
+the physics of those materials. In order to foster the understanding of
+piezoelectrics and ferroelectric and pave the way to future applications, the
+nanoscale characterization of these materials is essential. In this light, we
+have developed a novel AFM based mode that obtains a direct quantitative
+analysis of the piezoelectric coefficient d33. This nanoscale tool is capable
+of detecting and reveal piezo-charge generation through the direct
+piezoelectric effect at the surface of the piezoelectric and ferroelectric
+materials. We report the first nanoscale images of the charge generated in a
+thick single crystal of Periodically Poled Lithium Niobate (PPLN) and a Bismuth
+Ferrite (BiFO3) thin film by applying a force and recording the current
+produced by the materials. The quantification of both d33 coefficients for PPLN
+and BFO are 13 +- 2 pC/N and 46 +- 7 pC/N respectively, in agreement with the
+values reported in the literature. This new mode can operate simultaneously
+with PFM mode providing a powerful tool for the electromechanical and
+piezo-charge generation characterization of ferroelectric and piezoelectric
+materials.",1609.04250v1
+2016-10-14,Bidirectional particle transport and size selective sorting of Brownian particles in a flashing spatially periodic energy landscape,"We demonstrate a size sensitive experimental scheme which enables
+bidirectional transport and fractionation of paramagnetic colloids in a fluid
+medium. It is shown that two types of magnetic colloidal particles with
+different sizes can be simultaneously transported in opposite directions, when
+deposited above a stripe-patterned ferrite garnet film subjected to a
+square-wave magnetic modulation. Due to their different sizes, the particles
+are located at distinct elevations above the surface, and they experience two
+different energy landscapes, generated by the modulated magnetic substrate. By
+combining theoretical arguments and numerical simulations, we reveal such
+energy landscapes, which fully explain the bidirectional transport mechanism.
+The proposed technique does not require pre-imposed channel geometries such as
+in conventional microfluidics or lab-on-a-chip systems, and permits remote
+control over the particle motion, speed and trajectory, by using relatively low
+intense magnetic fields.",1610.04380v1
+2016-10-29,Tailoring magnetic insulator proximity effects in graphene: First-principles calculations,"We report a systematic first-principles investigation of the influence of
+different magnetic insulators on the magnetic proximity effect induced in
+graphene. Four different magnetic insulators are considered: two ferromagnetic
+europium chalcogenides namely EuO and EuS and two ferrimagnetic insulators
+yttrium iron garnet (YIG) and cobalt ferrite (CFO). The obtained
+exchange-splitting varies from tens to hundreds of meV. We also find an
+electron doping induced by YIG and europium chalcogenides substrates, that
+shift the Fermi level up to 0.78 eV and 1.3 eV respectively, whereas hole
+doping up to 0.5 eV is generated by CFO. Furthermore, we study the variation of
+the extracted exchange and tight binding parameters as a function of the EuO
+and EuS thicknesses. We show that those parameters are robust to thickness
+variation such that a single monolayer of magnetic insulator can induce a large
+magnetic proximity effect on graphene. Those findings pave the way towards
+possible engineering of graphene spin-gating by proximity effect especially in
+view of recent experiments advancement.",1610.09554v1
+2017-02-07,Giant-spin nonlinear response theory of magnetic nanoparticle hyperthermia: a field dependence study,"Understanding high-field amplitude electromagnetic heat loss phenomena is of
+great importance, in particular in the biomedical field, since the
+heat-delivery treatment plans might rely on analytical models that are only
+valid at low field amplitudes. Here, we develop a nonlinear response model
+valid for single- domain nanoparticles of larger particle sizes and higher
+field amplitudes in comparison to linear response theory. A nonlinear
+magnetization expression and a generalized heat loss power equation are
+obtained and compared with the exact solution of the stochastic
+Landau-Lifshitz-Gilbert equation assuming the giant-spin hypothesis. The model
+is valid within the hyperthermia therapeutic window and predicts a shift of
+optimum particle size and distinct heat loss field amplitude exponents.
+Experimental hyperthermia data with distinct ferrite-based nanoparticles, as
+well as third harmonic magnetization data supports the nonlinear model, which
+also has implications for magnetic particle imaging and magnetic thermometry.",1702.02022v1
+2017-03-22,Fabrication and magnetic control of Y3Fe5O12 cantilevers,"We have fabricated ferrite cantilevers in which their vibrational properties
+can be controlled by external magnetic fields. Submicron-scale cantilever
+structures were made from Y3Fe5O12 (YIG) films by physical etching combined
+with use of a focused ion beam milling technique. We found that the cantilevers
+exhibit two resonance modes which correspond to horizontal and vertical
+vibrations. Under external magnetic fields, the resonance frequency of the
+horizontal mode increases, while that of the vertical mode decreases,
+quantitatively consistent with our numerical simulation for magnetic forces.
+The changes in resonance frequencies with magnetic fields reach a few percent,
+showing that efficient magnetic control of resonance frequencies was achieved.",1703.07533v1
+2017-03-22,Coexistence of Interfacial Stress and Charge Transfer in Graphene Oxide based Magnetic Nanocomposites,"In this paper, we establish the existence of both compressive stress and
+charge transfer process in hydrothermally synthesized cobalt ferrite-graphene
+oxide (CoFe2O4/GO) nanocomposites. Transmission electron microscopy (TEM)
+results reveal the decoration of CoFe2O4 nanoparticles on GO sheets. Magnetic
+response of nanocomposites was confirme from superconducting quantum
+interference device (SQUID) magnetometer measurement. Optical properties of
+these nanocomposites were investigated by Raman spectroscopy. Interfacial
+compressive stress involved in this system is evaluated from observed blue
+shift of characteristic G peak of graphene oxide. Increase in full width
+half-maximum ( FWHM) as well as up shift in D and G peaks are clear indicator
+of involvement of charge transfer process between GO sheets and dispersed
+magnetic nanoparticles. The effect of charge transfer process is quantified in
+terms of shifting of Fermi level of these nanocomposites. This is evaluated
+from variation in contact surface potential difference (CPD) using Scanning
+Kelvin probe microscopy (SKPM). XRD spectra of CoFe2O4/GO confirm the
+polycrystalline nature of CoFe2O4 nanoparticles. Lattice strain estimated from
+XRD peaks are correlated to the observed Raman shift.",1703.07545v1
+2018-04-25,Nonreciprocity in microwave optomechanical circuits,"Nonreciprocal devices such as isolators and circulators are necessary to
+protect sensitive apparatus from unwanted noise. Recently, a variety of
+alternatives were proposed to replace ferrite-based commercial technologies,
+with the motivation to be integrated with microwave superconducting quantum
+circuits. Here, we review isolators realized with microwave optomechanical
+circuits and present a gyrator-based picture to develop an intuition on the
+origin of nonreciprocity in these systems. Such nonreciprocal optomechanical
+schemes show promise as they can be extended to circulators and directional
+amplifiers, with perspectives to reach the quantum limit in terms of added
+noise.",1804.09599v1
+2018-11-08,Quasistatic oscillations in subwavelength particles: Can one observe energy eigenstates?,"In increasing the capabilities of the optical and microwave techniques
+further into the subwavelength regime, quasistatic resonant structures has
+attracted considerable interest. Electromagnetic responses of electrostatic
+(ES) plasmon resonances in optics and magnetostatic (MS) magnon resonances in
+microwaves give rise to a strong enhancement of local fields near the surfaces
+of subwavelength particles. In the near-field regions of subwavelength
+particles one can only measure the electric or the magnetic field with
+accuracy. Such uncertainty in definition of the electric or magnetic field
+components raises the question of energy eigenstates of quasistatic
+oscillations. The energy eigenstate problem can be properly formulated when
+potential functions, used in the quasistatic-resonance problems, are introduced
+as scalar wave functions. In this case, one should observe quasistatic-wave
+retardation effects still staying in frames of the quasistatic description of
+oscillations in a subwavelength particle. In this paper, we analyze the problem
+of energy quantization of ES resonances in subwavelength optical metallic
+structures with plasmon oscillations and MS resonances in subwavelength
+microwave ferrite particles with magnon oscillations. We show that in a case of
+MS-potential scalar wave function one can observe quasistatic retardation
+effects and obtain a proper formulation of the energy eigenstate problem.",1811.03314v1
+2018-11-14,Enhancing nanoparticle diffusion on a unidirectional domain wall magnetic ratchet,"The performance of nanoscale magnetic devices is often limited by the
+presence of thermal fluctuations, while in micro-nanofluidic applications the
+same fluctuations may be used to spread reactants or drugs. Here we demonstrate
+the controlled motion and the enhancement of diffusion of magnetic
+nanoparticles that are manipulated and driven across a series of Bloch walls
+within an epitaxially grown ferrite garnet film. We use a rotating magnetic
+field to generate a traveling wave potential that unidirectionally transports
+the nanoparticles at a frequency tunable speed. Strikingly, we find an
+enhancement of diffusion along the propulsion direction and a frequency
+dependent diffusion coefficient that can be precisely controlled by varying the
+system parameters. To explain the reported phenomena, we develop a theoretical
+approach that shows a fair agreement with the experimental data enabling an
+exact analytical expression for the enhanced diffusivity above the magnetically
+modulated periodic landscape. Our technique to control thermal fluctuations of
+driven magnetic nanoparticles represents a versatile and powerful way to
+programmably transport magnetic colloidal matter in a fluid, opening the doors
+to different fluidic applications based on exploiting magnetic domain wall
+ratchets.",1811.05762v1
+2019-05-08,Gradient-enhanced statistical analysis of cleavage fracture,"We present a probabilistic framework for brittle fracture that builds upon
+Weibull statistics and strain gradient plasticity. The constitutive response is
+given by the mechanism-based strain gradient plasticity theory, aiming to
+accurately characterize crack tip stresses by accounting for the role of
+plastic strain gradients in elevating local strengthening ahead of cracks. It
+is shown that gradients of plastic strain elevate the Weibull stress and the
+probability of failure for a given choice of the threshold stress and the
+Weibull parameters. The statistical framework presented is used to estimate
+failure probabilities across temperatures in ferritic steels. The framework has
+the capability to estimate the three statistical parameters present in the
+Weibull-type model without any prior assumptions. The calibration against
+experimental data shows important differences in the values obtained for strain
+gradient plasticity and conventional J2 plasticity. Moreover, local probability
+maps show that potential damage initiation sites are much closer to the crack
+tip in the case of gradient-enhanced plasticity. Finally, the fracture response
+across the ductile-to-brittle regime is investigated by computing the cleavage
+resistance curves with increasing temperature. Gradient plasticity predictions
+appear to show a better agreement with the experiments.",1905.03221v1
+2019-05-30,Radio Frequency Magnet-free Circulators Based on Spatiotemporal Modulation of Surface Acoustic Wave Filters,"In this paper, a new generation of magnet-free circulators with high
+performance is proposed. Circulators are crucial devices in modern
+communication systems due to their ability to enable full-duplexing and double
+the spectral efficiency directly in the physical layer of the radio-frequency
+(RF) front-end. Traditionally, Lorentz reciprocity is broken by applying
+magnetic bias to ferrite materials, therefore conventional circulators are
+bulky and expensive. In this paper, this problem is addressed by replacing the
+magnetic bias with periodic spatiotemporal modulation. Compared to previous
+works, the proposed circulator is constructed using surface acoustic wave (SAW)
+filters instead of transmission lines (TL), which reduces the modulation
+frequency by at least a factor of 20 and ensures ultra-low power consumption
+and high linearity. The miniaturized high quality (Q) factor SAW filters also
+lead to a low-loss non-reciprocal band with strong isolation (IX) and broad
+bandwidth (BW) on a chip scale, therefore addressing such limitations in
+previous magnet-free demonstrations. Furthermore, compared to the conventional
+differential circuit configuration, a novel quad configuration is developed,
+which doubles the intermodulation-free bandwidth.",1905.13252v1
+2010-05-13,Short-Range B-site Ordering in Inverse Spinel Ferrite NiFe2O4,"The Raman spectra of single crystals of NiFe2O4 were studied in various
+scattering configurations in close comparison with the corresponding spectra of
+Ni0.7Zn0.3Fe2O4 and Fe3O4. The number of experimentally observed Raman modes
+exceeds significantly that expected for a normal spinel structure and the
+polarization properties of most of the Raman lines provide evidence for a
+microscopic symmetry lower than that given by the Fd-3m space group. We argue
+that the experimental results can be explained by considering the short range
+1:1 ordering of Ni2+ and Fe3+ at the B-sites of inverse spinel structure, most
+probably of tetragonal P4_122/P4_322 symmetry.",1005.2244v1
+2013-08-13,Interface states in CoFe2O4 spin-filter tunnel junctions,"Spin-filter tunneling is a promising way to generate highly spin-polarized
+current, a key component for spintronics applications. In this work we explore
+the tunneling conductance across the spin-filter material CoFe2O4 interfaced
+with Au electrodes, a geometry which provides nearly perfect lattice matching
+at the CoFe2O4/Au(001) interface. Using density functional theory calculations
+we demonstrate that interface states play a decisive role in controlling the
+transport spin polarization in this tunnel junction. For a realistic CoFe2O4
+barrier thickness, we predict a tunneling spin polarization of about -60%. We
+show that this value is lower than what is expected based solely on
+considerations of the spin-polarized band structure of CoFe2O4, and therefore
+that these interface states can play a detrimental role. We argue this is a
+rather general feature of ferrimagnetic ferrites and could make an important
+impact on spin-filter tunneling applications.",1308.3461v1
+2014-03-20,Magnetization of densely packed interacting magnetic nanoparticles with cubic and uniaxial anisotropies: A Monte Carlo study,"The magnetization curves of densely packed single domain magnetic
+nanoparticles (MNP) are investigated by Monte Carlo simulations in the
+framework of an effective one spin model. The particles whose size
+polydispersity is taken into account are arranged in spherical clusters and
+both dipole dipole interactions (DDI) and magnetic anisotropy energy (MAE) are
+included in the total energy. Having in mind the special case of spinel
+ferrites of intrinsic cubic symmetry, combined cubic and uniaxial
+magnetocrystalline anisotropies are considered with different configurations
+for the orientations of the cubic and uniaxial axes. It is found that the DDI,
+together with a marked reduction of the linear susceptibility are responsible
+for a damping of the peculiarities due to the MAE cubic component on the
+magnetization. As an application, we show that the simulated magnetization
+curves compare well to experimental results for $\gamma$--Fe$_2$O$_3$ MNP for
+small to moderate values of the field.",1403.5157v1
+2017-01-05,Transforming Single Domain Magnetic CoFe2O4 Nanoparticles from Hydrophobic to Hydrophilic By Novel Mechanochemical Ligand Exchange,"Single phase, uniform size (~9 nm) Cobalt Ferrite (CFO) nanoparticles have
+been synthesized by hydrothermal synthesis using oleic acid as a surfactant.
+The as synthesized oleic acid coated CFO (OA-CFO) nanoparticles were well
+dispersible in nonpolar solvents but not dispersible in water. The OA-CFO
+nanoparticles have been successfully transformed to highly water dispersible
+citric acid coated CFO (CA-CFO) nanoparticles using a novel single step ligand
+exchange process by mechanochemical milling, in which small chain citric acid
+molecules replace the original large chain oleic acid molecules available on
+CFO nanoparticles. The contact angle measurement shows that OA-CFO
+nanoparticles are hydrophobic whereas CA-CFO nanoparticles are superhydrophilic
+in nature. The potentiality of as synthesized OA-CFO and mechanochemically
+transformed CA-CFO nanoparticles for the demulsification of highly stabilized
+water-in-oil and oil-in-water emulsions has been demonstrated.",1701.01410v1
+2017-01-08,Nonlocal magnon spin transport in NiFe$_2$O$_4$ thin films,"We report magnon spin transport in nickel ferrite (NiFe$_2$O$_4$, NFO)/
+platinum (Pt) bilayer systems at room temperature. A nonlocal geometry is
+employed, where the magnons are excited by the spin Hall effect or by the Joule
+heating induced spin Seebeck effect at the Pt injector, and detected at a
+certain distance away by the inverse spin Hall effect at the Pt detector. The
+dependence of the nonlocal magnon spin signals as a function of the magnetic
+field is closely related to the NFO magnetization behavior. In contrast, we
+observe that the magnetoresistance measured locally at the Pt injector does not
+show a clear relation with the average NFO magnetization. We estimate the
+magnon spin relaxation length to be 3.1 $\pm$ 0.2 $\mu$m in the investigated
+NFO samples.",1701.02041v2
+2011-11-08,Analysis of the Collective Behavior of a 10 by 10 Array of Fe3O4 Dots in a Large Micromagnetic Simulation,"We report a full (3D) micromagnetic simulation of a set of 100 ferrite
+(Fe$_3$O$_4$) cylindrical dots, arranged in a 10 by 10 square (planar) array of
+side 3.27 $\mu$m, excited by an external in-plane magnetic field. The resulting
+power spectrum of magnetic excitations and the dynamical magnetization field at
+the resulting resonance modes were investigated. The absorption spectrum
+deviates considerably from that of a single particle reference simulation,
+presenting a mode-shifting and splitting effect. We found an inversion symmetry
+through the center of the array, in the sense that each particle and its
+inversion counterpart share approximately the same magnetization mode behavior.
+Magnonic designs aiming at synchronous or coherent tunings of spin-wave
+excitations at given spatially separated points within a regular square array
+may benefit from the new effects here described.",1111.1866v1
+2012-04-03,Two-pulse stimulated echo in magnets,"The results of experimental study of two-pulse stimulated echo in
+ferromagnets of two types are presented. Ferromagnet Co and half-metal Co MnSi
+2, in which a single-pulse echo formed by the distortion mechanism of the
+fronts of exciting pulse is also observed, are classified among the first type.
+Lithium ferrite and intermetal compound MnSb characterized by the absence of
+single-pulse echo in them - belong to the second type. For signals of two-pulse
+stimulated echo in the materials of the first type a short time and a long time
+of relaxations are observed. The short time is about the order of value shorter
+less than the spin-spin relaxation time. The long time is close to the
+transverse relaxation time of single-pulse echo formed by the distortion
+mechanism. The mechanisms that provide the possible interpretations of the
+peculiarities of the processes of nuclear magnetic relaxation are discussed.",1204.0686v2
+2012-04-26,Peculiarities of timing and spectral diagrams of magnetic video-pulse excitation influence on NMR spin-echo in magnets,"We present the first systematic study of timing and spectral diagrams of
+magnetic video-pulse influence on the NMR two-pulse echo in a number of magnets
+(ferromagnets, ferrites, half metals, intermetals). It is shown that the timing
+diagrams showing the dependence of two-pulse echo intensity on the temporal
+location of a magnetic video-pulse in respect to radio-frequency pulses and the
+spectral diagrams of this influence are defined mainly by the local hyperfine
+field anisotropy and domain walls mobility. These diagrams could be used for
+the identification of the nature of NMR spectra in multidomain magnetic
+materials and to improve the resolution capacity of the NMR method in magnets.",1204.5844v1
+2013-09-20,High values of Ferroelectric polarization and magnetic susceptibility in BFO nanorods,"Remarkably high values of polarization as well as a significant magnetic
+susceptibility have been observed in multiferroic Bismuth Ferrite (BFO) in the
+form of nanorods protruding out. These were developed on porous Anodised
+Alumina (AAO) templates using wet chemical technique. Diameters of nanorods are
+in the range of 20-100 nm. The high values of polarization and magnetic
+susceptibility are attributed to the BFO nanorod structures giving rise to the
+directionality. There is no leakage current in P-E loop examined at various
+frequencies. Magnetocapacitance measurements reflect a significant enhancement
+in magnetoelectric coupling also.",1309.5218v2
+2013-09-23,Remarkably high value of Capacitance in BiFeO3 Nanorod,"A remarkably high value of specific capacitance of 450 F/g has been observed
+through electrochemical measurements in the electrode made of multiferroic
+Bismuth Ferrite (BFO) in the form of nanorods protruding out. These BFO
+nanorods were developed on porous Anodised Alumina (AAO) templates using wet
+chemical technique. Diameters of nanorods were in the range of 20-100 nm. The
+high capacitance is attributed to the nanostructure. The active surface charge
+has been evaluated electrochemically by cyclic voltammetry (CV) at different
+scanning rates and charge-discharge studies. The specific capacitances were
+constant after several cycles of charge-discharge leading to their useful
+application in devices. The mechanism of accumulation of charge on the
+electrode surface has been studied.",1309.5690v1
+2014-06-05,Magnetic properties of epitaxial Fe$_3$O$_4$ films with various crystal orientations and TMR effect in room temperature,"Fe$_3$O$_4$ is a ferrimagnetic spinel ferrite that exhibits electric
+conductivity at room temperature (RT). Although the material has been predicted
+to be a half metal according to ab-initio calculations, magnetic tunnel
+junctions (MTJs) with Fe$_3$O$_4$ electrodes have demonstrated a small tunnel
+magnetoresistance effect. Not even the sign of the TMR ratio has been
+experimentally established. Here, we report on the magnetic properties of
+epitaxial Fe$_3$O$_4$ films with various crystal orientations. The films
+exhibited apparent crystal orientation dependence on hysteresis curves. In
+particular, Fe$_3$O$_4$(110) films exhibited in-plane uniaxial magnetic
+anisotropy. With respect to the squareness of hysteresis, Fe$_3$O$_4$ (111)
+demonstrated the largest squareness. Furthermore, we fabricated MTJs with
+Fe$_3$O$_4$(110) electrodes, and obtained an TMR effect of -12\% at RT. The
+negative TMR ratio corresponded to the negative spin polarization of
+Fe$_3$O$_4$ predicted from band calculations.",1406.1296v1
+2014-06-14,Electric-field coupling to spin waves in a centrosymmetric ferrite,"We experimentally demonstrate that the spin-orbit interaction can be utilized
+for direct electric-field tuning of the propagation of spin waves in a
+single-crystal yttrium iron garnet magnonic waveguide. Magnetoelectric coupling
+not due to the spin-orbit interaction, and hence an order of magnitude weaker,
+leads to electric-field modification of the spin-wave velocity for waveguide
+geometries where the spin-orbit interaction will not contribute. A theory of
+the phase shift, validated by the experiment data, shows that, in the exchange
+spin wave regime, this electric tuning can have high efficiency. Our findings
+point to an important avenue for manipulating spin waves and developing
+electrically tunable magnonic devices.",1406.3675v1
+2014-06-16,An air-cooled Litz wire coil for measuring the high frequency hysteresis loops of magnetic samples : a useful setup for magnetic hyperthermia applications,"A low-cost and simple setup for measuring the high-frequency hysteresis loops
+of magnetic samples is described. An AMF in the range 6-100 kHz with amplitude
+up to 80 mT is produced by a Litz wire coil. The latter is air-cooled using a
+forced-air approach so no water flow is required to run the setup.
+High-frequency hysteresis loops are measured using a system of pick-up coils
+and numerical integration of signals. Reproducible measurements are obtained in
+the frequency range of 6-56 kHz. Measurement examples on ferrite cylinders and
+on iron oxide nanoparticle ferrofluids are shown. Comparison with other
+measurement methods of the hysteresis loop area (complex susceptibility,
+quasi-static hysteresis loops and calorific measurements) is provided and shows
+the coherency of the results obtained with this setup. This setup is well
+adapted to the magnetic characterization of colloidal solutions of MNPs for
+magnetic hyperthermia applications.",1406.4013v1
+2014-06-20,Linear magnetoelectricity at room temperature in perovskite superlattices by design,"Discovering materials that display a linear magnetoelectric effect at room
+temperature is challenge. Such materials could facilitate novel devices based
+on the electric-field control of magnetism. Here we present simple, chemically
+intuitive design rules to identify a new class of bulk magnetoelectric
+materials based on the 'bicolor' layering of $Pnma$ ferrite perovskites, e.g.,
+LaFeO$_3$/ LnFeO$_3$ superlattices for which Ln = lanthanide cation. We use
+first-principles density-functional theory calculations to confirm these ideas.
+Additionally, we elucidate the origin of this effect and show it is a general
+consequence of the layering of any bicolor, $Pnma$ perovskite superlattice in
+which the number of constituent layers are odd (leading to a form of hybrid
+improper ferroelectricity) and Goodenough- Kanamori rules. Here, the polar
+distortions induce both weak ferromagnetism and a linear magnetoelectric
+effect. Our calculations suggest that the effect is 2-3 times greater in
+magnitude than that observed for the prototypical magnetoelectric material,
+Cr$_2$O$_3$. We use a simple mean field model to show that the considered
+materials order magnetically above room temperature.",1406.5488v1
+2015-12-04,Magnetoelectric-field microwave antennas: Far-field orbital angular momenta from chiral-topology near fields,"The near fields in the proximity of a small ferrite particle with
+magnetic-dipolar-mode (MDM) oscillations have space and time symmetry
+breakings. Such MDM originated fields, called magnetoelectric (ME) fields,
+carry both spin and orbital angular momentums. By virtue of unique topology, ME
+fields are strongly different from free-space electromagnetic (EM) fields. In
+this paper, we show that because of chiral topology of ME fields in a nearfield
+region, far-field orbital angular momenta (OAM) can be observed, both
+numerically and experimentally. In a single element antenna, we obtain a
+radiation pattern with an angular squint. We reveal that in far field microwave
+radiation a crucial role is played by the ME energy distribution in the
+near-field region.",1512.01393v1
+2015-12-18,Cross-spectrum Measurement of Thermal-noise Limited Oscillators,"Cross-spectrum analysis is a commonly-used technique for the detection of
+phase and amplitude noise of a signal in the presence of interfering noise. It
+extracts the desired correlated noise from two time series in the presence of
+uncorrelated interfering noise. Recently, we demonstrated that the
+phase-inversion (anti-correlation) effect due to AM noise leakage can cause
+complete or partial collapse of the cross-spectral function. In this paper, we
+discuss the newly discovered effect of anti-correlated thermal noise that
+originates from the common-mode power divider (splitter), an essential
+component in a cross-spectrum noise measurement system. We studied this effect
+for different power splitters and discuss its influence on the measurement of
+thermal-noise limited oscillators. An oscillator whose thermal noise is
+primarily set by the 50 ohm source resistance is referred to as a
+thermally-limited oscillator. We provide theory, simulation and experimental
+results. In addition, we expand this study to reveal how the presence of
+ferrite-isolators and amplifiers at the output ports of the power splitters can
+affect the oscillator noise measurements. Finally, we discuss a possible
+solution to overcome this problem.",1512.06160v1
+2016-05-10,Engineering topological materials in microwave cavity arrays,"We present a scalable architecture for the exploration of interacting
+topological phases of photons in arrays of microwave cavities, using
+established techniques from cavity and circuit quantum electrodynamics. A
+time-reversal symmetry breaking (non-reciprocal) flux is induced by coupling
+the microwave cavities to ferrites, allowing for the production of a variety of
+topological band structures including the $\alpha=1/4$ Hofstadter model.
+Effective photon-photon interactions are included by coupling the cavities to
+superconducting qubits, and are sufficient to produce a $\nu=1/2$ bosonic
+Laughlin puddle. We demonstrate by exact diagonalization that this architecture
+is robust to experimentally achievable levels of disorder. These advances
+provide an exciting opportunity to employ the quantum circuit toolkit for the
+exploration of strongly interacting topological materials.",1605.03177v1
+2016-05-24,Autocatalytic mechanism of pearlite transformation in steel,"A model of pearlite colony formation in carbon steels with ab-initio
+parameterization is proposed. The model describes the process of decomposition
+of austenite and cementite formation through a metastable intermediate
+structure by taking into account the increase of the magnetic order under the
+cooling. Autocatalytic mechanism of pearlite colony formation and the
+conditions for its implementation have been analyzed. We demonstrate that
+pearlite with lamellar structure is formed by autocatalytic mechanism when
+thermodynamic equilibrium between the initial phase (austenite) and the
+products of its decomposition (cementite and ferrite) does not take place. By
+using model expression for free energy with first-principles parameterization
+we find conditions of formation of both lamellar and globular structures, in
+agreement with experiment. The transformation diagram is suggested and
+different scenarios in the kinetics of decomposition are investigated by phase
+field simulations.",1605.07508v2
+2016-08-26,Optimization of nanocomposite materials for permanent magnets by micromagnetic simulations: effect of the intergrain exchange and the hard grains shape,"In this paper we perform the detailed numerical analysis of remagnetization
+processes in nanocomposite magnetic materials consisting of magnetically hard
+grains (i.e. grains made of a material with a high magnetocrystalline
+anisotropy) embedded into a magnetically soft phase. Such materials are widely
+used for the production of permanent magnets, because they combine the high
+remanence with the large coercivity. We perform simulations of nanocomposites
+with Sr-ferrite as the hard phase and Fe or Ni as the soft phase, concentrating
+our efforts on analyzing the effects of ({\it i}) the imperfect intergrain
+exchange and ({\it ii}) the non-spherical shape of hard grains. We demonstrate
+that - in contrast to the common belief - the maximal energy product is
+achieved not for systems with the perfect intergrain exchange, but for
+materials where this exchange is substantially weakened. We also show that the
+main parameters of the hysteresis loop - remanence, coercivity and the energy
+product - exhibit non-trivial dependencies on the shape of hard grains, and
+provide detailed explanations for our results. Simulation predictions obtained
+in this work open new ways for the optimization of materials for permanent
+magnets.",1608.07429v1
+2017-06-15,Preliminary corrosion studies of IN-RAFM steel with stagnant Lead Lithium at 550 C,"Corrosion of Indian RAFMS (reduced activation ferritic martensitic steel)
+material with liquid metal, Lead Lithium ( Pb-Li) has been studied under static
+condition, maintaining Pb-Li at 550 C for different time durations, 2500, 5000
+and 9000 hours. Corrosion rate was calculated from weight loss measurements.
+Microstructure analysis was carried out using SEM and chemical composition by
+SEM-EDX measurements. Micro Vickers hardness and tensile testing were also
+carried out. Chromium was found leaching from the near surface regions and
+surface hardness was found to decrease in all the three cases. Grain boundaries
+were affected. Some grains got detached from the surface giving rise to pebble
+like structures in the surface micrographs. There was no significant reduction
+in the tensile strength, after exposure to liquid metal. This paper discusses
+the experimental details and the results obtained.",1706.05000v1
+2017-06-26,Magnetic Proximity Effect in Pt/CoFe2O4 Bilayers,"We observe the magnetic proximity effect (MPE) in Pt/CoFe2O4 bilayers grown
+by molecular beam epitaxy. This is revealed through angle-dependent
+magnetoresistance measurements at 5 K, which isolate the contributions of
+induced ferromagnetism (i.e. anisotropic magnetoresistance) and spin Hall
+effect (i.e. spin Hall magnetoresistance) in the Pt layer. The observation of
+induced ferromagnetism in Pt via AMR is further supported by density functional
+theory calculations and various control measurements including insertion of a
+Cu spacer layer to suppress the induced ferromagnetism. In addition, anomalous
+Hall effect measurements show an out-of-plane magnetic hysteresis loop of the
+induced ferromagnetic phase with larger coercivity and larger remanence than
+the bulk CoFe2O4. By demonstrating MPE in Pt/CoFe2O4, these results establish
+the spinel ferrite family as a promising material for MPE and spin manipulation
+via proximity exchange fields.",1706.08473v1
+2017-06-22,Investigation on nickel ferrite nanowire device exhibiting negative differential resistance $-$ a first-principles investigation,"The electronic property of NiFe$_2$O$_4$ nanowire device is investigated
+through nonequilibrium Green's functions (NEGF) in combination with density
+functional theory (DFT). The electronic transport properties of NiFe$_2$O$_4$
+nanowire are studied in terms of density of states, transmission spectrum and
+$I{-}V$ characteristics. The density of states gets modified with the applied
+bias voltage across NiFe$_2$O$_4$ nanowire device, the density of charge is
+observed both in the valence band and in the conduction band on increasing the
+bias voltage. The transmission spectrum of NiFe$_2$O$_4$ nanowire device gives
+the insights on the transition of electrons at different energy intervals. The
+findings of the present work suggest that NiFe$_2$O$_4$ nanowire device can be
+used as negative differential resistance (NDR) device and its NDR property can
+be tuned with the bias voltage, which may be used in microwave device, memory
+devices and in fast switching devices.",1706.10148v1
+2017-10-24,Peculiar metastable structural state in carbon steel,"The kinetics of phase transformations at cooling of carbon steel in
+dependence on the temperature of preliminary annealing T$_{an}$ is studied. It
+is shown that the cooling from T$_{an}$ > A$_3$ (i. e. above the temperature of
+ferrite start) with the rate 90 - 100 K/s results in structural state which
+essentially dependent on T$_{an}$; at 750$^0$C < T$_{an}$ < 830$^0$C the
+transformation is of perlite type whereas at T$_{an}$ > 830$^0$C the
+martensitic structure arises. Our results evidence the formation of a special
+structural state in a certain range of temperatures near and above the boundary
+of two phase region which is characterized by a substantially nanoscale
+heterogeneity in carbon distribution, lattice distortions, and magnetic
+short-range order.",1710.08604v1
+2017-12-16,Contrasting magnetoelectric behavior in multiferroic hexaferrites as understood by crystal symmetry analyses,"Magnetoelectric (ME) properties under rotating magnetic field H are
+comparatively investigated in two representative hexaferrites Y-type
+Ba0.5Sr1.5Zn2(Fe0.92Al0.08)12O22 and Z-type Ba0.52Sr2.48Co2Fe24O41, both of
+which have exhibited a similar transverse conical spin structure and giant ME
+coupling near room temperature. When the external H is rotated clockwise by
+2pi, in-plane P vector is rotated clockwise by 2pi in the Y-type hexaferrite
+and counterclockwise by 4pi in the Z-type hexaferrite. A symmetry-based
+analysis reveals that the faster and opposite rotation of P vector in the
+Z-type hexaferrite is associated with the existence of a mirror plane
+perpendicular to c-axis. Moreover, such a peculiar crystal symmetry also
+results in contrasting microscopic origins for the spin-driven
+ferroelectricity; only the inverse DM interaction is responsible for the Y-type
+hexaferrite while additional p-d hybridization becomes more important in the
+Z-type hexaferrite. This work demonstrates the importance of the crystal
+symmetry in the determination of ME properties in the hexaferrites and provides
+a fundamental framework for understanding and applying the giant ME coupling in
+various ferrites with hexagonal crystal structure.",1712.05928v1
+2018-10-07,Gazing at crystal balls: Electron backscatter diffraction pattern analysis and cross correlation on the sphere,"We present spherical analysis of electron backscatter diffraction (EBSD)
+patterns with two new algorithms: (1) band localisation and band profile
+analysis using the spherical Radon transform; (2) orientation determination
+using spherical cross correlation. These new approaches are formally introduced
+and their accuracies are determined using dynamically simulated patterns. We
+demonstrate their utility with an experimental dataset obtained from ferritic
+iron. Our results indicate that the analysis of EBSD patterns on the surface of
+the sphere provides an elegant method of revealing information from these rich
+sources of crystallographic data.",1810.03211v4
+2019-06-03,Oxygen-vacancy induced magnetic phase transitions in multiferroic thin films,"Multiferroics in which giant ferroelectric polarization and magnetism coexist
+are of tremendous potential for engineering disruptive applications in
+information storage and energy conversion. Yet the functional properties of
+multiferroics are thought to be affected detrimentally by the presence of point
+defects, which may be abundant due to the volatile nature of some constituent
+atoms and high temperatures involved in materials preparation. Here, we
+demonstrate with theoretical methods that oxygen vacancies may enhance the
+functionality of multiferroics by radically changing their magnetic
+interactions in thin films. Specifically, oxygen vacancies may restore missing
+magnetic super-exchange interactions in large axial ratio phases, leading to
+full antiferromagnetic spin ordering, and induce the stabilization of
+ferrimagnetic states with a significant net magnetization of 0.5 uB per formula
+unit. Our theoretical study should help to clarify the origins of long-standing
+controversies in bismuth ferrite and improve the design of technological
+applications based on multiferroics.",1906.01117v1
+2019-06-11,Proximity magnetoresistance in graphene induced by magnetic insulators,"We demonstrate the existence of Giant proximity magnetoresistance (PMR)
+effect in a graphene spin valve where spin polarization is induced by a nearby
+magnetic insulator. PMR calculations were performed for yttrium iron garnet
+(YIG), cobalt ferrite (CFO), and two europium chalcogenides EuO and EuS. We
+find a significant PMR (up to 100%) values defined as a relative change of
+graphene conductance with respect to parallel and antiparallel alignment of two
+proximity induced magnetic regions within graphene. Namely, for high Curie
+temperature (Tc) CFO and YIG insulators which are particularly important for
+applications, we obtain 22% and 77% at room temperature, respectively. For low
+Tc chalcogenides, EuO and EuS, the PMR is 100% in both cases. Furthermore, the
+PMR is robust with respect to system dimensions and edge type termination. Our
+findings show that it is possible to induce spin polarized currents in graphene
+with no direct injection through magnetic materials.",1906.04469v1
+2019-09-06,Unveiling multiferroic proximity effect in graphene,"We demonstrate that electronic and magnetic properties of graphene can be
+tuned via proximity of multiferroic substrate. Our first-principles
+calculations performed both with and without spin-orbit coupling clearly show
+that by contacting graphene with bismuth ferrite BiFeO$_3$ (BFO) film, the
+spin-dependent electronic structure of graphene is strongly impacted both by
+the magnetic order and by electric polarization in the underlying BFO. Based on
+extracted Hamiltonian parameters obtained from the graphene band structure, we
+propose a concept of six-resistance device based on exploring multiferroic
+proximity effect giving rise to significant proximity electro- (PER), magneto-
+(PMR), and multiferroic (PMER) resistance effects. This finding paves a way
+towards multiferroic control of magnetic properties in two dimensional
+materials.",1909.02844v1
+2019-09-07,Designing rare-earth free permanent magnets in Heusler alloys via interstitial doping,"Based on high-throughput density functional theory calculations, we
+investigated the effects of light interstitial H, B, C, and N atoms on the
+magnetic properties of cubic Heusler alloys, with the aim to design new
+rare-earth free permanent magnets. It is observed that the interstitial atoms
+induce significant tetragonal distortions, leading to 32 candidates with large
+($>$ 0.4 MJ/m$^3$) uniaxial magneto-crystalline anisotropy energies (MAEs) and
+10 cases with large in-plane MAEs. Detailed analysis following the the
+perturbation theory and chemical bonding reveals the strong MAE originates from
+the local crystalline distortions and thus the changes of the chemical bonding
+around the interstitials. This provides a valuable way to tailor the MAEs to
+obtain competitive permanent magnets, filling the gap between high performance
+Sm-Co/Nd-Fe-B and widely used ferrite/AlNiCo materials.",1909.03275v1
+2019-10-15,Achievements and New Challenges for CERN's Digital LLRF Family,"An innovative digital Low-Level RF (LLRF) family has been developed at CERN
+and deployed on several circular machines. Operation of CERN's PS Booster
+(PSB), Low Energy Ion Ring (LEIR) and Extra Low ENergy Antiproton (ELENA) ring
+all reaped great benefit from the flexibility and processing power of this new
+family. Beam and cavity feedback loops have been implemented, as well as bunch
+shaping, longitudinal blowup and bunch splitting. For ELENA, longitudinal
+diagnostics such as bunched beam intensity and bunch length measurements have
+also been deployed. During Long Shutdown 2 (LS2) the ferrite-based High-Level
+RF (HLRF) systems of the Antiproton Decelerator (AD) and of the four-ring PSB
+will be replaced with Finemet-based HLRF. This will require a new LLRF system
+for the AD and deep upgrades to the existing PSB LLRF systems. This paper gives
+an overview of the main results achieved by the digital LLRF family so far and
+of the challenges the LLRF team will take on during LS2.",1910.06643v1
+2020-01-09,"High temperature thermal cycling effect on the irreversible responses of lattice structure, magnetic properties and electrical conductivity in Co$_{2.75}$Fe$_{0.25}$O$_{4+δ}$ spinel oxide","We report high temperature synchrotron X-ray diffraction (SXRD), dc
+magnetization and current-voltage (I-V) characteristics for the samples of
+Co$_{2.75}$Fe$_{0.25}$O$_4$ ferrite. The material was prepared by chemical
+reaction of the Fe and Co nitrate solutions at pH = 11 and subsequent annealing
+at temperatures 200 0C, 500 0C and 900 0C. The measurements were performed by
+cycling the temperature from 300 K to high temperature (warming mode) and
+return back to 300 K (cooling mode). The SXRD patterns indicated a fine
+bi-phased cubic spinel structure in the highly Co rich spinel oxide.
+Magnetization curves showed intrinsic ferrimagnetic features and defect induced
+additional ferromagnetic phase at higher temperatures. Electrical conductivity
+showed thermal hysteresis loop between warming and cooling modes of temperature
+variation. The samples exhibited new information on the irreversibility
+phenomena of lattice structure, magnetization and electrical conductivity on
+cycling the measurement temperatures.",2001.02829v2
+2020-01-27,Non-exponential magnetic relaxation in magnetic nanoparticles for hyperthermia,"Magnetic nanoparticle based hyperthermia emerged as a potential tool for
+treating malignant tumours. The efficiency of the method relies on the
+knowledge of magnetic properties of the samples; in particular, knowledge of
+the frequency dependent complex magnetic susceptibility is vital to optimize
+the irradiation conditions and to provide feedback for material science
+developments. We study the frequency-dependent magnetic susceptibility of an
+aqueous ferrite suspension for the first time using non-resonant and resonant
+radiofrequency reflectometry. We identify the optimal measurement conditions
+using a standard solenoid coil, which is capable of providing the complex
+magnetic susceptibility up to 150 MHz. The result matches those obtained from a
+radiofrequency resonator for a few discrete frequencies. The agreement between
+the two different methods validates our approach. Surprisingly, the dynamic
+magnetic susceptibility cannot be explained by an exponential magnetic
+relaxation behavior even when we consider a particle size-dependent
+distribution of the relaxation parameter.",2001.09774v1
+2020-02-11,Diffusion of single active-dipolar cubes in applied fields,"""Active matter"" refers to a class of out-of-equilibrium systems whose ability
+to transform environmental energy to kinetic energy is sought after in multiple
+fields of science and at very different length scales. At microscopic scales,
+an important challenge lies in overpowering the particles reorientation due to
+thermal fluctuations, especially in nano-sized systems, to create non-random,
+directed motion, needed for a wide range of possible applications. In this
+article, we employ molecular dynamics simulations to show that the diffusion of
+a self-propelling dipolar nanocube can be enhanced in a pre-defined direction
+with the help of a moderately strong applied magnetic field, overruling the
+effect of the thermal fluctuations. Furthermore, we show that the direction of
+diffusion is given by the orientation of the net internal magnetisation of the
+cube. This can be used to determine experimentally the latter in synthetically
+crafted active cobalt ferrite nanocubes.",2002.04299v2
+2021-01-19,Role of interface morphology on the martensitic transformation in pure Fe,"Using classical molecular dynamics simulations, we study austenite to ferrite
+phase transformation in iron, focusing on the role of interface morphology. We
+compare two different morphologies; a \textit{flat} interface in which the two
+phases are joined according to Nishiyama-Wasserman orientation relationship vs.
+a \textit{ledged} one, having steps similar to the vicinal surface. We identify
+the atomic displacements along a misfit dislocation network at the interface
+leading to the phase transformation. In case of \textit{ledged} interface,
+stacking faults are nucleated at the steps, which hinder the interface motion,
+leading to a lower mobility of the inter-phase boundary, than that of flat
+interface. Interestingly, we also find the temperature dependence of the
+interface mobility to show opposite trends in case of \textit{flat} vs.
+\textit{ledged} boundary. We believe that our study is going to present a
+unified and comprehensive view of martensitic transformation in iron with
+different interface morphology, which is lacking at present, as \textit{flat}
+and \textit{ledged} interfaces are treated separately in the existing
+literature.",2101.07468v1
+2012-05-21,Resistive and ferritic-wall plasma dynamos in a sphere,"We numerically study the effects of varying electric conductivity and
+magnetic permeability of the bounding wall on a kinematic dynamo in a sphere
+for parameters relevant to Madison plasma dynamo experiment (MPDX). The dynamo
+is excited by a laminar, axisymmetric flow of von Karman type. The flow is
+obtained as a solution to the Navier-Stokes equation for an isothermal fluid
+with a velocity profile specified at the sphere's boundary. The properties of
+the wall are taken into account as thin-wall boundary conditions imposed on the
+magnetic field. It is found that an increase in the permeability of the wall
+reduces the critical magnetic Reynolds number Rm_cr. An increase in the
+conductivity of the wall leaves Rm_cr unaffected, but reduces the dynamo growth
+rate.",1205.4696v1
+2017-05-12,High voltage charging system for pulsed power generators,"A robust and portable power supply has been developed specifically for
+charging linear transformer drivers, a modern incarnation of fast pulsed power
+generators. It is capable of generator +100 kV and -100 kV at 1 mA, while
+withstanding the large voltage spikes generated when the pulsed-power generator
+is triggered. The three-stage design combines a zero-voltage switching circuit,
+a step-up transformer using ferrite cores, and a dual Cockcroft-Walton voltage
+multiplier. The zero-voltage switching circuit drives the primary of the
+transformer in parallel with a capacitor. With this driver, the tank circuit
+naturally remain in its resonant state, allowing for maximum energy coupling
+between the zero-voltage switching circuit and the Cockcroft-Walton voltage
+multiplier across a wide range of loading conditions.",1705.06240v2
+2017-05-24,Control of single-mode operation in a circular waveguide filled by a longitudinally magnetized gyroelectromagnetic medium,"A substantial control of dispersion features of the hybrid EH01 and HE11
+modes of a circular waveguide which is completely filled by a longitudinally
+magnetized composite finely-stratified ferrite-semiconductor structure is
+discussed. A relation between the resonant conditions of such a composite
+gyroelectromagnetic filling of the circular waveguide and dispersion features
+of the supported modes are studied. Three distinct frequency bands with the
+single-mode operation under normal as well as anomalous dispersion conditions
+of the EH01 mode are identified by solving an optimization problem with respect
+to the filling factors of the composite medium. The possibility of achieving
+isolated propagation of the HE11 mode is revealed.",1705.08603v1
+2018-03-26,Uniaxial anisotropy and enhanced magnetostriction of CoFe$_2$O$_4$ induced by reaction under uniaxial pressure with SPS,"In this study, we have compared magnetic and magnetostrictive properties of
+polycrystalline CoFe$_2$O$_4$ pellets, produced by three different methods,
+focusing on the use of Spark Plasma Sintering (SPS). This technique allows a
+very short heat treatment stage while a uniaxial pressure is applied. SPS was
+utilized to sinter cobalt ferrite but also to make the reaction and the
+sintering (reactive sintering) of the same ceramic composition. Magnetic and
+magnetostrictive measurements show that the reactive sintering with SPS induces
+a uniaxial anisotropy, while it is not the case with a simple sintering
+process. The induced anisotropy is then expected to be a consequence of the
+reaction under uniaxial pressure. This anisotropy enhanced the magnetostrictive
+properties of the sample, where a maximum longitudinal magnetostriction of
+$-229$~ppm is obtained. This process can be a promising alternative to the
+magnetic-annealing because of the short processing time required (22 minutes).",1803.09656v1
+2018-07-24,Enhanced magnon spin transport in NiFe$_2$O$_4$ thin films on a lattice-matched substrate,"We investigate magnon spin transport in epitaxial nickel ferrite
+(NiFe$_2$O$_4$, NFO) films grown on magnesium gallate spinel (MgGa$_2$O$_4$,
+MGO) substrates, which have a lattice mismatch with NFO as small as 0.78%,
+resulting in the reduction of antiphase boundary defects and thus in improved
+magnetic properties in the NFO films. In the nonlocal transport experiments,
+enhanced signals are observed for both electrically and thermally excited
+magnons, and the magnon relaxation length ($\lambda_m$) of NFO is found to be
+around 2.5 $\mu$m at room temperature. Moreover, at both room and low
+temperatures, we present distinct features from the nonlocal spin Seebeck
+signals which arise from magnon polaron formation. Our results demonstrate
+excellent magnon transport properties (magnon spin conductivity, $\lambda_m$
+and spin mixing conductance at the interface between Pt) of NFO films grown on
+a lattice-matched substrate that are comparable with those of yttrium iron
+garnet.",1807.09013v1
+2018-08-22,Microwave Conductivity of Ferroelectric Domains and Domain Walls in Hexagonal Rare-earth Ferrite,"We report the nanoscale electrical imaging results in hexagonal
+$Lu_{0.6}Sc_{0.4}FeO_3$ single crystals using conductive atomic force
+microscopy (C-AFM) and scanning microwave impedance microscopy (MIM). While the
+dc and ac response of the ferroelectric domains can be explained by the surface
+band bending, the drastic enhancement of domain wall (DW) ac conductivity is
+clearly dominated by the dielectric loss due to DW vibration rather than
+mobile-carrier conduction. Our work provides a unified physical picture to
+describe the local conductivity of ferroelectric domains and domain walls,
+which will be important for future incorporation of electrical conduction,
+structural dynamics, and multiferroicity into high-frequency nano-devices.",1808.07208v1
+2018-12-20,Size-dependent bistability in multiferroic nanoparticles,"Most multiferroic materials with coexisting ferroelectric and magnetic order
+exhibit cycloidal antiferromagnetism with wavelength of several nanometers. The
+prototypical example is bismuth ferrite (BiFeO$_3$ or BFO), a room-temperature
+multiferroic considered for a number of technological applications. While most
+applications require small sizes such as nanoparticles, little is known about
+the state of these materials when their sizes are comparable to the cycloid
+wavelength. This work describes a microscopic theory of cycloidal magnetism in
+nanoparticles based on Hamiltonian calculations. It is demonstrated that
+magnetic anisotropy close to the surface has a huge impact on the multiferroic
+ground state. For certain nanoparticle sizes the modulus of the ferromagnetic
+and ferroelectric moments are bistable, an effect that may be used in the
+design of ideal memory bits that can be switched electrically and read out
+magnetically.",1812.08297v4
+2018-12-21,Structural and Magnetic Characterization of Spin Canted Mixed Ferrite-Cobaltites: LnFe0.5Co0.5O3 (Ln = Eu and Dy),"The mixed ferrite-cobaltites LnFe0.5Co0.5O3, with Ln = Eu & Dy have been
+prepared by a sol-gel method and the samples have been characterized using
+X-ray diffraction and electron microscopy. The magnetic investigations reveal
+that both samples ordered in canted antiferromagnetic structures near room
+temperature. The Dzyaloshinskii-Moriya or antisymmetric exchange interaction
+induces weak ferromagnetism due to canting of the antiferromagnetically ordered
+spins. In the case of Ln-Fe-Co orthoferrites, two magnetic sublattices (Ln3+-4f
+and Fe3+/Co3+-3d) generally align in opposite directions and interesting
+temperature dependent phenomena: e.g. uncompensated antiferromagnetic
+sublattices and spin-reorientations, are observed in the system. The existence
+of hysteresis at low temperature region has been explained in terms of the
+strength of magnetic interactions between Fe3+ and Co3+ ions with different
+A-site rare earth cations.",1812.09031v2
+2019-02-19,Magnetic interaction and anisotropy axes arrangement in nanoparticle aggregates can enhance or reduce the effective magnetic anisotropy,"The magnetic response of nanostructures plays an important role on biomedical
+applications being strongly influenced by the magnetic anisotropy. In this work
+we investigate the role of temperature, particle concentration and nanoparticle
+arrangement forming aggregates in the effective magnetic anisotropy of Mn-Zn
+ferrite-based nanoparticles. Electron magnetic resonance and coercivity
+temperature dependence analyses, were critically compared for the estimation of
+the anisotropy. We found that the temperature dependence of the anisotropy
+follows the Callen-Callen model, while the symmetry depends on the particle
+concentration. At low concentration one observes only an uniaxial term, while
+increasing a cubic contribution has to be added. The effective anisotropy was
+found to increase the higher the particle concentration on magnetic colloids,
+as long as the easy axis was at the same direction of the nanoparticle chain.
+Increasing even further the concentration up to a highly packed condition
+(powder sample) one observes a decrease of the anisotropy, that was attributed
+to the random anisotropy axes configuration.",1902.07188v1
+2019-08-07,Tunability of Room Temperature Ferromagnetism in Spintronic Semiconductors through Non-magnetic Atoms,"The implementation and control of room temperature ferromagnetism (RTFM) by
+adding magnetic atoms to a semiconductor's lattice has been one of the most
+important problems in solid state state physics in the last decade. Herein we
+report for the first time, to our knowledge, on the mechanism that allows RTFM
+to be tuned by the inclusion of \emph{non-magnetic} aluminum in nickel ferrite.
+This material, NiFe$_{2-x}$Al$_x$O$_4$ (x=0, 0.5, 1.5), has already shown much
+promise for magnetic semiconductor technologies, and we are able to add to its
+versatility technological viability with our results. The site occupancies and
+valencies of Fe atoms (Fe$^{3+}$ T$_d$, Fe$^{2+}$ O$_h$, and Fe$^{3+}$ O$_h$)
+can be methodically controlled by including aluminum. Using the fact that
+aluminum strongly prefers a 3+ octahedral environment, we can selectively fill
+iron sites with aluminum atoms, and hence specifically tune the magnetic
+contributions for each of the iron sites, and therefore the bulk material as
+well. Interestingly, the influence of the aluminum is weak on the electronic
+structure (supplemental material), allowing one to retain the desirable
+electronic properties while achieving desirable magnetic properties.",1908.02610v1
+2019-08-14,A Tuneable Magnetic Domain Wall Conduit Regulating Nanoparticle Diffusion,"We demonstrate a general and robust method to confine on a plane strongly
+diffusing submicrometer particles in water by using size tunable magnetic
+channels. These virtual conduits are realized with pairs of movable Bloch walls
+(BWs) located within an epitaxially grown ferrite garnet film. We show that,
+once inside the magnetic conduit, the particles experience an effective local
+parabolic potential in the transverse direction, while freely diffusing along
+the conduit. The stiffness of the magnetic potential is determined as a
+function of field amplitude which varies the width of the magnetic channel, and
+precise control of the degree of confinement is demonstrated by tuning the
+applied field. The magnetic conduit is then used to realize single files of
+non-passing particles and to induce periodic condensation of an ensemble of
+particles into parallel stripes in a completely controllable and reversible
+manner.",1908.05039v1
+2019-08-20,"Design of a High Strength, High Ductility 12 wt% Mn Medium Manganese Steel With Hierarchical Deformation Behaviour","A novel medium Mn steel of composition Fe-12Mn-4.8Al-2Si-0.32C-0.3V was
+manufactured with 1.09 GPa yield strength, 1.26 GPa tensile strength and 54%
+elongation. The thermomechanical process route was designed to be industrially
+translatable and consists of hot and then warm rolling before a 30 min
+intercritical anneal. The resulting microstructure comprised of coarse
+elongated austenite grains in the rolling direction surrounded by necklace
+layers of fine austenite and ferrite grains. The tensile behaviour was
+investigated by in-situ neutron diffraction and the evolution of microstructure
+studied with Electron Backscattered Diffraction (EBSD). It was found that the
+coarse austenite grains contributed to the first stage of strain hardening by
+transforming into martensite and the fine austenite necklace grains contributed
+to the second stage of strain hardening by a mixture of twinning and
+transformation induced plasticity (TWIP and TRIP) mechanisms. This hierarchical
+deformation behaviour contributed to the exceptional ductility of this steel.",1908.07258v3
+2019-11-08,First principles calculation of shift current in chalcopyrite semiconductor ZnSnP$_2$,"The bulk photovoltaic effect generates intrinsic photocurrents in materials
+without inversion symmetry. Shift current is one of the bulk photovoltaic
+phenomena related to the Berry phase of the constituting electronic bands:
+photo-excited carriers coherently shift in real space due to the difference in
+the Berry connection between the valence and conduction bands. Ferroelectric
+semiconductors and Weyl semimetals are known to exhibit such nonlinear optical
+phenomena. Here we consider chalcopyrite semiconductor ZnSnP$_2$ which lacks
+inversion symmetry and calculate the shift current conductivity. We find that
+the magnitude of the shift current is comparable to the recently measured
+values on other ferroelectric semiconductors and an order of magnitude larger
+than bismuth ferrite. The peak response for both optical and shift current
+conductivity, which mainly comes from P-3$p$ and Sn-5$p$ orbitals, is several
+eV above the bandgap.",1911.03376v2
+2019-11-20,Polymer-bonded anisotropic SrFe$_\text{12}$O$_\text{19}$ filaments for fused filament fabrication,"In this publication we describe the extrusion process and the properties of
+polymer-bonded anisotropic SrFe$_\text{12}$O$_\text{19}$ filaments for fused
+filament fabrication (FFF). Highly filled polyamide 12 filaments with a filling
+fraction from 40 vol.% to 55 vol.% are mixed and extruded into filaments with a
+diameter of 1.75 mm. Such filaments are processable with a conventional FFF 3D
+printer. No modifications of the 3D printer are necessary. Detailed mechanical
+and magnetic investigations of printed samples are performed and discussed. In
+the presence of an external alignment field, the Sr ferrite particles inside
+the PA12 matrix can be aligned along an external magnetic field. The remanence
+can be increased by 40 % by printing anisotropic structures. For the 55 vol.%
+filled filament, a remanence of 212.8 mT and a coercivity of 307.4 mT are
+measured. The capabilities of printing magnetic anisotropic structures in a
+complex external field are presented with a Halbach-array arrangement. By the
+aim of an inverse field model, based on a finite element method, the
+orientation of the particles and the quality of the print can be estimated by a
+nondestructive method.",1911.08869v1
+2019-12-09,Optical vortex-induced forward mass transfer: Manifestation of helical trajectory of optical vortex,"The orbital angular momentum of an optical vortex field is found to twist
+high viscosity donor material to form a micron-scale 'spin jet'. This unique
+phenomenon manifests the helical trajectory of the optical vortex. Going beyond
+both the conventional ink jet and laser induced forward mass transfer (LIFT)
+patterning technologies, it also offers the formation and ejection of a
+micron-scale 'spin jet' of the donor material even with an ultrahigh viscosity
+of 4 Pas. This optical vortex laser induced forward mass transfer (OV-LIFT)
+patterning technique will enable the development of next generation printed
+photonic/electric/spintronic circuits formed of ultrahigh viscosity donor dots
+containing functional nanoparticles, such as quantum dots, metallic particles
+and magnetic ferrite particles, with ultrahigh spatial resolution. It can also
+potentially explore a completely new needleless drug injection.",1912.03907v1
+2019-12-16,3D printing of polymer-bonded anisotropic magnets in an external magnetic field and by a modified production process,"The possibility of producing polymer-bonded magnets with the aid of additive
+processes, such as 3D printing, opens up a multitude of new areas of
+application. Almost any structures and prototypes can be produced
+cost-effectively in small quantities. Extending the 3D printing process allows
+the manufacturing of anisotropic magnetic structures by aligning the magnetic
+easy axis of ferromagnetic particles inside a paste-like compound material
+along an external magnetic field. This is achieved by two different approaches:
+First, the magnetic field for aligning the particles is provided by a permanent
+magnet. Secondly, the 3D printing process itselfs generates an anisotropic
+behavior of the structures. An inexpensive and customizable end-user fused
+filament fabrication 3D printer is used to print the magnetic samples. The
+magnetical properties of different magnetic anisotropic Sr ferrite and SmFeN
+materials are investigated and discussed.",1912.07374v1
+2020-05-12,Magnetically induced topological transitions of hyperbolic dispersion in biaxial gyrotropic media,"Magnetically induced topological transitions of isofrequency surfaces of bulk
+waves propagating through an unbounded biaxial gyrotropic medium are studied.
+The medium is constructed from a two-component superlattice composed of
+magnetized ferrite and semiconductor layers. To derive the constitutive
+parameters of the gyrotropic medium, a homogenization procedure from the
+effective medium theory is applied. The study is carried out in the frequency
+range near the frequency of ferromagnetic resonance, where the magnetic
+subsystem possesses the properties of natural hyperbolic dispersion. The
+topological transitions from an open type-I hyperboloid to several intricate
+hyperbolic-like forms are demonstrated for the extraordinary waves. We reveal
+how realistic material losses change the form of isofrequency surface
+characterizing hyperbolic dispersion. The obtained results broaden our
+knowledge on the possible topologies of isofrequency surfaces that can appear
+in gyrotropic media influenced by an external static magnetic field.",2005.05875v1
+2021-02-13,Highly efficient parallel grand canonical simulations of interstitial-driven deformation-diffusion processes,"Diffusion of interstitial alloying elements like H, O, C, and N in metals and
+their continuous relocation and interactions with their microstructures have
+crucial influences on metals properties. However, besides limitations in
+experimental tools in capturing these mechanisms, the inefficiency of numerical
+tools also inhibits modeling efforts. Here, we present an efficient framework
+to perform hybrid grand canonical Monte Carlo and molecular dynamics
+simulations that allow for parallel insertion/deletion of Monte Carlo moves. A
+new methodology for calculation of the energy difference at trial moves that
+can be applied to many-body potentials as well as pair ones is a primary
+feature of our implementation. We study H diffusion in Fe (ferrite phase) and
+Ni polycrystalline samples to demonstrate the efficiency and scalability of the
+algorithm and its application. The computational cost of using our framework
+for half a million atoms is a factor of 250 less than the cost of using
+existing libraries.",2102.06980v1
+2021-02-15,Patterning enhanced tetragonality in BiFeO3 thin films with effective negative pressure by helium implantation,"Helium implantation in epitaxial thin films is a way to control the
+out-of-plane deformation independently from the in-plane strain controlled by
+epitaxy. In particular, implantation by means of a helium microscope allows for
+local implantation and patterning down to the nanometer resolution, which is of
+interest for device applications. We present here a study of bismuth ferrite
+(BiFeO3) films where strain was patterned locally by helium implantation. Our
+combined Raman, XRD and TEM study shows that the implantation causes an
+elongation of the BiFeO3 unit cell and ultimately a transition towards the
+so-called super-tetragonal polymorph via states with mixed phases. In addition,
+TEM reveals the onset of amorphization at a threshold dose that does not seem
+to impede the overall increase in tetragonality. The phase transition from the
+R-like to T-like BiFeO3 appears as first-order in character, with regions of
+phase coexistence and abrupt changes in lattice parameters.",2102.07557v1
+2021-02-16,Magnetic phase diagram of rare-earth orthorhombic perovskite oxides,"Spin reorientation and magnetisation reversal are two important features of
+the rare-earth orthorhombic provskites ($RM$O$_{3}$'s) that have attracted a
+lot of attention, though their exact microscopic origin has eluded researchers.
+Here, using density functional theory and classical atomistic spin dynamics we
+build a general Heisenberg magnetic model that allows to explore the whole
+phase diagram of the chromite and ferrite compounds and to scrutinize the
+microscopic mechanism responsible for spin reorientations and magnetisation
+reversals. We show that the occurrence of a magnetization reversal transition
+depends on the relative strength and sign of two interactions between
+rare-earth and transition-metal atoms: superexchange and Dzyaloshinsky-Moriya.
+We also conclude that the presence of a smooth spin reorientation transition
+between the so-called $\Gamma_4$ and the $\Gamma_2$ phases through a coexisting
+region, and the temperature range in which it occurs, depends on subtle balance
+of metal--metal (superexchange and Dzyaloshinsky-Moriya) and metal--rare-earth
+(Dzyaloshinsky-Moriya) couplings. In particular, we show that the intermediate
+coexistence region occurs because the spin sublattices rotate at different
+rates.",2102.08152v1
+2021-03-03,Operating a passive on-chip superconducting circulator: device control and quasiparticle effects,"Microwave circulators play an important role in quantum technology based on
+superconducting circuits. The conventional circulator design, which employs
+ferrite materials, is bulky and involves strong magnetic fields, rendering it
+unsuitable for integration on superconducting chips. One promising design for
+an on-chip superconducting circulator is based on a passive Josephson-junction
+ring. In this paper, we consider two operational issues for such a device:
+circuit tuning and the effects of quasiparticle tunneling. We compute the
+scattering matrix using adiabatic elimination and derive the parameter
+constraints to achieve optimal circulation. We then numerically optimize the
+circulator performance over the full set of external control parameters,
+including gate voltages and flux bias, to demonstrate that this
+multi-dimensional optimization converges quickly to find optimal working
+points. We also consider the possibility of quasiparticle tunneling in the
+circulator ring and how it affects signal circulation. Our results form the
+basis for practical operation of a passive on-chip superconducting circulator
+made from a ring of Josephson junctions.",2103.02759v2
+2021-03-09,Specific loss power of magnetic nanoparticles (fluid) hyperthermia in non-adiabatic conditions,"We investigate the magnetic nanoparticles (fluid) hyperthermia in
+non-adiabatic conditions through the calorimetric method. Specifically, we
+propose a theoretical approach to magnetic hyperthermia from a thermodynamic
+point of view. To test the robustness of the approach, we perform hyperthermia
+experiments and analyze the thermal behavior of magnetite and magnesium ferrite
+magnetic nanoparticles dispersed in water submitted to an alternating magnetic
+field. From our findings, besides estimating the specific loss power value from
+a non-adiabatic process, thus enhancing the accuracy in the determination of
+this quantity, we provide physical meaning to parameters found in literature
+that still remained not fully understood, and bring to light how they can be
+obtained experimentally.",2103.05691v1
+2021-03-22,Spin-dependent optical excitations in LiFeO2,"The three-dimensional ternary LiFeO2 compound presents various unusual
+essential properties. The main features are thoroughly explored by the density
+functional and many-body perturbation theory. The concise physical/chemical
+picture, the critical spin-polarizations and orbital hybridizations in the Li-O
+and Fe-O bonds, are clearly examined through geometric optimization,
+quasi-particle energy spectra, spin-polarized density of states, the spatial
+charge densities, the spin-density distributions, and the strong optical
+responses. The unusual optical transitions cover various frequency-dependent
+absorption structures, and the most prominent plasmon modes are identified by
+the dielectric functions, energy loss functions, reflectance spectra, and
+absorption coefficients. Optical excitations are anisotropic and strongly
+affected by excitonic effects. The close combinations of electronic, magnetic
+and optical properties allow us to identify the significant spin-polarizations
+and orbital hybridizations for each available excitation channel. The lithium
+ferrite compound can be used for spintronic and photo-catalysis applications.",2103.11838v3
+2021-03-31,Slip band interactions and GND latent hardening in a galling resistant stainless steel,"Slip activation, slip band interactions, and GND densities in iron-base,
+galling resistant alloy Nitronic 60 have been characterised at the grain length
+scale using small-scale mechanical testing with high resolution digital image
+correlation and high-angular resolution electron backscatter diffraction. By
+correlating the two measurement techniques, new insight into slip band
+interactions, the generation of lattice curvature and the corresponding
+accumulation of geometrically necessary dislocations (GNDs) is provided.
+Multiple discrete slip bands are typically active within single grains,
+resulting in significant slip band interactions. Crossing slip bands were found
+to generate accumulations of GNDs. Regions where slip bands block other slip
+bands were associated with the highest GND densities, in excess of three time
+the densities of crossing slip bands. Representative crystal plasticity
+modelling investigations have demonstrated that discrete slip blocking events
+are responsible for locally elevated GND density. This behaviour is
+rationalised in terms of lattice curvature associated with the differing levels
+of constraint provided by the crossing or blocking-type behaviours. Ferrite
+grains are also found to contribute to the generation of GNDs. Together, these
+two effects provide significant work hardening mechanisms, likely to be key to
+the development of future iron-base hard facing alloys.",2103.16864v1
+2021-04-01,Missing level statistics in a dissipative microwave resonator with partially violated time-reversal invariance,"We report on the experimental investigation of the fluctuation properties in
+the resonance frequency spectra of a flat resonator simulating a dissipative
+quantum billiard subject to partial time-reversal invariance violation (TIV)
+which is induced by two magnetized ferrites. The cavity has the shape of a
+quarter bowtie billiard of which the corresponding classical dynamics is
+chaotic. Due to dissipation it is impossible to identify a complete list of
+resonance frequencies. Based on a random-matrix theory approach we derive
+analytical expressions for statistical measures of short- and long-range
+correlations in such incomplete spectra interpolating between the cases of
+preserved time-reversal invariance and complete TIV and demonstrate their
+applicability to the experimental spectra.",2104.02572v1
+2021-04-20,Magnetic dipolar modes in magnon-polariton condensates,"For dipole-carrying excitations observed in a high-quality resonator,
+strong-coupling modes can appear as composite bosons with the spontaneous
+formation of quantized vortices in the condensed phase of a polariton fluid. In
+exciton-polaritons, in particular, it leads to sustained trapping of the
+emitted photon. In this paper, we show that magnon-polaritons can be realized
+due to magnon condensation caused by magnetic dipole-dipole interaction. In a
+quasi-2D ferrite disk placed in a microwave cavity, one observes quantum
+confinement effects of magnetic-dipolar-mode (MDM) oscillations. These modes,
+characterized by energy eigenstates with rotational superflows and quantized
+vortices, are exhibited as spinor condensates. Along with the condensation of
+MDM magnons in the quasi-2D disk of the magnetic insulator, electric dipole
+condensation is also observed. At the MDM resonances, transfer between angular
+momenta in the magnetic insulator and in the vacuum cavity, demonstrates
+generation of vortex flows with fixed handedness. This indicates unique
+topological properties of polariton wavefronts. One observes curved wavefronts
+and effects of supperradiance in microwave structures. In an environment of
+scattering states of microwave waveguide, EM waves can carry the topological
+phases of MDM resonances.",2104.10048v1
+2021-05-06,Interfacial strain relief by periodic dislocation doublets emerging from rotationally related orientation relationships of Y4Zr3O12 dispersions in ferrite matrix,"The trigonal/bcc orientation relationships (ORs) and their likelihood of
+occurrence are extensively studied using dispersed Y4Zr3O12nano-precipitates in
+bcc Fe matrix by means of transmission electron microscopy, image simulations,
+and a crystallographic model. Two orientation relationships related by a
+rotation:[1-20]||[111] with (21-2)||(-110) and [1-20]||[111] with
+(00-3)||(-110), are established and periodic arrays of misfit dislocation
+doublets are identified at the strained interface in (110) for both ORs.
+Further eighteen energetically feasible ORs in Y4Zr3O12/bcc system are deduced
+by combining stereographic projections, which include the two predominant ORs
+in this study and other ORs in literature. The orientation relationship which
+generates the interface with a minimum number of dislocation doublets is the
+most frequent.",2105.02530v1
+2021-05-27,Pushing the Study of Point Defects in Thin Film Ferrites to Low Temperatures Using In Situ Ellipsometry,"Unveiling point defects concentration in transition metal oxide thin films is
+essential to understand and eventually control their functional properties,
+employed in an increasing number of applications and devices. Despite this
+unquestionable interest, there is a lack of available experimental techniques
+able to estimate the defect chemistry and equilibrium constants in such oxides
+at intermediate-to-low temperatures. In this study, the defect chemistry of a
+relevant material such as La1-xSrxFeO3-d (LSF) with (x = 0.2, 0.4 and 0.5
+(LSF20, LSF40 and LSF50 respectively) is obtained by using a novel in situ
+spectroscopic ellipsometry approach applied to thin films. Through this
+technique, the concentration of holes in LSF is correlated to measured optical
+properties and its evolution with temperature and oxygen partial pressure is
+determined. In this way, a systematic description of defect chemistry in LSF
+thin films in the temperature range from 350dC to 500dC is obtained for the
+first time, which represents a step forward in the understanding of LSF20,
+LSF40 and LSF50 for emerging low temperature applications.",2105.13039v1
+2021-05-31,Effect of Zr and Al Addition on Nanocluster Formation in Oxide Dispersion Strenghthened Steel-an ab initio Study,"Conventional Oxide dispersion strengthened steels are characterized by
+thermally stable, high density of Y-Ti-O nanoclusters, which are responsible
+for their high creep strength. Ti plays a major role in obtaining a high
+density of ultrafine particles of optimum size range of 2-10 nm. In
+Al-containing ODS steels developed for corrosion resistance, Y-Al-O clusters
+formed are of size range 20 -100 nm, and Ti fails in making dispersions finer
+in the presence of Al. Usage of similar alloying elements like Zr in place of
+Ti is widely considered. In this study, binding energies of different stages of
+Y-Zr-O-Vacancy and Y-Al-O-Vacancy complexes in the bcc Iron matrix are studied
+by first-principle calculations. It is shown that in all the stages of
+formation, Y-Zr-O-Vacancy clusters have higher binding energy than
+Y-Al-O-Vacancy clusters and hence in ferritic steel containing both Zr and Al,
+Y-Zr-O-Vacancy clusters are more stable and more favored to nucleate than
+Y-Al-O-Vacancy clusters. The bonding nature in each stage is analyzed using
+charge density difference plots for the plausible reason for higher stability
+of Y-Zr-O-Vacancy clusters.",2105.15063v1
+2021-06-24,Chiral Quantum Network with Giant Atoms,"In superconducting quantum circuits (SQCs), chiral routing quantum
+information is often realized with the ferrite circulators, which are usually
+bulky, lossy and require strong magnetic fields. To overcome those problems, we
+propose a novel method to realize chiral quantum networks by exploiting giant
+atom effects in SQC platforms. By assuming each coupling point being modulated
+with time, the interaction becomes momentum-dependent, and giant atoms will
+chirally emit photons due to interference effects. The chiral factor can
+approach 1, and both the emission direction and rate can be freely tuned by the
+modulating signals. We demonstrate that a high-fidelity state transfer between
+remote giant atoms can be realized. Our proposal can be integrated on the
+superconducting chip easily, and has the potential to work as a tunable toolbox
+for quantum information processing in future chiral quantum networks.",2106.13187v3
+2021-06-23,Highly Linear Nonmagnetic Circulator Enabled By A Temporal Nonreciprocal Phase Shifter,"Conventional circulators are made of magnetic ferrites and suffer from a
+cumbersome architecture, incompatibility with integrated circuit technology and
+inability for high frequency applications. To overcome these limitations, here
+we propose a lightweight low-profile non-magnetic circulator comprising a
+nonreciprocal time-varying phase shifter. This circulator is composing a
+nonreciprocal temporal phase shifter and two reciprocal delay-line-based phase
+shifters. The proposed nonreciprocal temporal phase shifter is based on the
+generation of time-harmonic signals, enforcing destructive interference for
+undesired time harmonics and constructive interference for desired time
+harmonics at different locations of the structure. Such a unique task is
+accomplished through two phase-engineered temporal loops. The phase and
+frequency of these two loops are governed by external signals with different
+phases, imparting an effective electronic angular momentum to the system. We
+observe large isolation level of greater than 32 dB, a P1dB of +31.7 dBm and
+IIP3 of +42.4 dBm. Furthermore, this circulator is endowed with a
+reconfigurable architecture and can be directly embedded in a conventional
+integrated circuit (IC) technology to realize a class of high power handling
+and linear IC circulators.",2107.09788v1
+2021-07-21,Spin orbit torque switching of antiferromagnet through the Neel reorientation in rare-earth ferrite,"We suggest coherent switching of canted antiferromagnetic (AFM) spins using
+spin-orbit torque (SOT) in small magnet. The magnetic system of orthoferrite
+features biaxial easy anisotropy and the Dzyaloshinskii Moriya interaction,
+which is perpendicular to the easy axes and therefore creates weak
+magnetization (m). A damping-like component of the SOT induces N\'eel
+reorientation along one of the easy axes and then exerts torque on m, leading
+to tilting of the N\'eel order l. The torque on the magnetization becomes
+stronger due to coupling with the induced Oersted field or the field-like
+component of the SOT, enhancing the tilting of l. Therefore, l is found to
+experience deterministic switching after the SOT is turned off. Based upon both
+numerical and analytical analysis of the coherent switching, XOR logic gates
+are also found to be implemented in a single magnetic layer. In addition, we
+investigate how magnetic parameters affect the critical reorientation angle and
+current density in a simple layered structure of platinum and a canted AFM. Our
+findings are expected to provide an alternative spin-switching mechanism for
+ultrafast applications such as spin logic and electronic devices.",2107.10156v1
+2021-09-09,Identification of object composition with Magnetic Inductive Tomography,"The inductive response of an object to an oscillating magnetic field reveals
+information about its electrical conductivity and magnetic permeability. Here
+we introduce a technique that uses measurements of the angular, frequency and
+spatial dependence of the inductive signal to determine object composition.
+Identification is performed by referencing an object's inductive response to
+that of materials with mutually exclusive properties such as copper (high
+electric conductivity, negligible magnetic permeability) and ferrite
+(negligible electric conductivity, high magnetic permeability). The technique
+uses a sensor with anisotropic sensitivity to discriminate between the
+different characters of the eddy current and magnetisation driven object
+responses. Experimental validation of the method is performed through Magnetic
+Induction Tomography measurement with a radio-frequency atomic magnetometer.
+Possible applications of the technique in security screening devices are
+discussed.",2109.04074v1
+2021-11-02,Anti-PT-symmetry-enhanced interconversion between microwave and optical fields,"The intrinsic dissipation of systems into a shared reservoir introduces
+coherence between two systems, enabling anti-Parity-Time (anti-PT) symmetry. In
+this paper, we propose an anti-PT symmetric converter, consisting of a
+microwave cavity coupled dissipatively to a ferromagnetic sphere, which
+supports significant improvements in the conversion efficiency when compared to
+coherently coupled setups. In particular, when only the ferrite sample is
+driven, the strong coherence induced by the vacuum of the mediating channel
+leads to much stronger enhancements in the intended conversion. The enhancement
+is an inalienable artifact of the emergence of a long-lived, dark mode
+associated with a quasi-real singularity of the hybrid system. In addition, we
+observe considerable asymmetry in the efficiencies of microwave-to-optical and
+optical-to-microwave conversions, in spite of the symmetrical structure of the
+trilinear optomagnonic coupling stimulating both the transduction phenomena.
+The nonreciprocity stems from the intrinsic asymmetry in the couplings of the
+microwave and optical fields to the cavity-magnon network as well as the phase
+coupling entailed by the spatial separation.",2111.01335v1
+2021-11-26,Deep Learning for automated phase segmentation in EBSD maps. A case study in Dual Phase steel microstructures,"Electron Backscattering Diffraction (EBSD) provides important information to
+discriminate phase transformation products in steels. This task is
+conventionally performed by an expert, who carries a high degree of
+subjectivity and requires time and effort. In this paper, we question if
+Convolutional Neural Networks (CNNs) are able to extract meaningful features
+from EBSD-based data in order to automatically classify the present phases
+within a steel microstructure. The selected case of study is ferrite-martensite
+discrimination and U-Net has been selected as the network architecture to work
+with. Pixel-wise accuracies around ~95% have been obtained when inputting raw
+orientation data, while ~98% has been reached with orientation-derived
+parameters such as Kernel Average Misorientation (KAM) or pattern quality.
+Compared to other available approaches in the literature for phase
+discrimination, the models presented here provided higher accuracies in shorter
+times. These promising results open a possibility to work on more complex steel
+microstructures.",2112.03072v1
+2021-12-08,Micromechanical fatigue experiments for validation of microstructure-sensitive fatigue simulation models,"Crack initiation governs high cycle fatigue life and is susceptible to
+microstructural details. While corresponding microstructure-sensitive models
+are available, their validation is difficult. We propose a validation framework
+where a fatigue test is mimicked in a sub-modeling simulation by embedding the
+measured microstructure into the specimen geometry and adopting the
+experimental boundary conditions. Exemplary, a phenomenological crystal
+plasticity model was applied to predict deformation in ferritic steel
+(EN1.4003). Hotspots in commonly used fatigue indicator parameter maps are
+compared with damage segmented from micrographs. Along with the data, the
+framework is published for benchmarking future micromechanical fatigue models.",2112.04342v1
+2021-12-31,Tunable magnetic field source for magnetic field imaging microscopy,"In this work we present a novel, compact, power efficient magnetic field
+source design for magnetic field imaging microscopy. The device is based on a
+pair of diametrically magnetized permanent magnet cylinders with
+electro-mechanical rotation control and ferrite field concentrators. A Hall
+probe and NV centers in diamond are used to demonstrate a proof of concept of a
+proposed magnetic field setup and to characterise the homogeneity of the
+produced magnetic field on a micrometer scale. Numerical simulation results are
+compared with experimental results showing good agreement of the distribution
+of the magnetic field in the setup. As a result, a magnetic field source with a
+tunable field amplitude in the range from 1 mT to 222 mT is demonstrated,
+achieving a magnetic field homogeneity of 2 ppm/$\mu$m or 0.5 $\mu$T/$\mu$m at
+222 mT in a 25$\times$25 $\mu$m field of view.",2112.15359v1
+2022-01-02,Symmetry analysis of magnetoelectric effects in perovskite-based multiferroics,"In this article, we perform the symmetry analysis of perovskite-based
+multiferroics: bismuth ferrite (BiFeO3)-like, orthochromites (RCrO3), and
+Ruddlesden-Popper perovskites (Ca3Mn2O7-like), being the typical
+representatives of multiferroics of the trigonal, rhombic, and tetragonal
+crystal families and explore the effect of crystallographic distortions on
+magnetoelectric properties. We determine the principal order parameters for
+each of the considered structures and obtain their invariant combinations
+consistent with the particular symmetry. This approach allowed us to analyze
+the features of the magnetoelectric effect observed during structural phase
+transitions in BixR1-xFeO3 compounds and show that the rare-earth sublattice
+gives an impact into the linear magnetoelectric effect allowed by the symmetry
+of the new structure. It is shown that the magnetoelectric properties of
+ortho-chromites are attributed to the couplings between the magnetic and
+electric dipole moments arising near Cr3+ ions due to distortions linked with
+rotations and deformations of the CrO6 octahedra. For the first time, such
+symmetry consideration was implemented in the analysis of the Ruddlesden-Popper
+structures, which demonstrates the possibility of realizing the magnetoelectric
+effect in the Ruddlesden-Popper phases containing magnetically active cations
+and allows to estimate conditions required for its optimization.",2201.00316v1
+2022-01-25,Stability and low-energy orientations of interphase boundaries in multiaxial ferroelectrics: Phase-field simulations,"The coexistence of different ferroelectric phases enables the tunability of
+the macroscopic properties and extensive applications from piezoelectric
+transducers to nonvolatile memories. Here we develop a thermodynamic model to
+predict the stability and low-energy orientations of boundaries between
+different phases in ferroelectrics. Taking lead zirconate titanate and bismuth
+ferrite as two examples, we demonstrate that the low-energy orientations of
+interphase boundaries are largely determined by minimizing the electrostatic
+and elastic energies. Phase-field simulations are employed to analyze the
+competition between the interfacial energy and the electrostatic and elastic
+energies. Our simulation results demonstrate that the lowering of crystal
+symmetry could occur due to the electrical and mechanical incompatibilities
+between the two phases, which can be used to explain the experimentally
+observed low-symmetry phases near morphotropic phase boundaries. Our work
+provides theoretical foundations for understanding and controlling the
+interphase boundaries in ferroelectric materials for multifunctional
+applications.",2201.10074v1
+2022-02-13,Kinetic Monte Carlo modelling of Helium Bubble Nucleation onto Oxides in the Fe-Ti-Y-O System,"A Kinetic Monte Carlo (KMC) model was created to simulate the insertion of
+transmutation He atoms into nanostructured ferritic alloys (NFAs) under neutron
+irradiation. Interstitial He atoms migrate through the NFA until becoming
+trapped in bubbles of other He atoms and vacancies created from irradiation.
+The Y-Ti-O nano-oxides in the NFAs were found to be effective in capturing
+these He atoms and preventing bubbles from forming at the grain boundary and
+appear to replicate the characteristics (size and number density) observed in
+other experiments. The bubbles were found to prefer the <111> oxide interface
+as a nucleation site and the stable bubbles have a He/Vac ratio between 1.3 and
+1.8 He/Vac. The influence of He bubbles on the segregation of solutes to the
+grain boundaries or on the stability of the nano-oxides were negligible.",2202.06189v1
+2022-03-08,Coupling between improper ferroelectricity and ferrimagnetism in hexagonal ferrites,"Antisymmetric Dzyaloshinskii-Moriya (DM) interactions generating from the
+spin-orbit coupling induce various fascinating properties, like magnetoelectric
+(ME) effect, weak ferromagnetism and non-trivial topological spin textures like
+skyrmions, in real materials. Compared to their symmetric isotropic exchange
+counterpart, these interactions are generally of a weaker order of strength,
+creating modest twisting in the spin structure which results in weak
+ferromagntism or weak linear ME effect. Our proposed two-sublattice model, in
+contrast, predicts a hitherto unobserved, charge ordered non-collinear
+ferrimagnetic behavior with a considerably high magnetization $\textbf{M}$
+coexisting with a ferroelectric (FE) order with an electric polarization
+$\textbf{P}$ and a strong cross coupling between them which is primarily driven
+by the inter-sublattice DM interactions. The key to realize these effects is
+the coupling between these microscopic interactions and the FE primary order
+parameter. We predict microscopic mechanisms to achieve electric field
+$\textbf{E}$ induced spin-reorientation transitions and 180$^{\circ}$ switching
+of the direction of $\textbf{M}$. This model was realized in the hexagonal
+phase of LuFeO$_3$ doped with electrons. This system shows $P \sim$ 15
+$\mu$C/cm$^2$, $M \sim$ 1.3 $\mu_B$/Fe and magnetic transition near room
+temperature ($\sim$ 290 K). Our theoretical results are expected to stimulate
+further quest for energy-efficient routes to control magnetism for spintronics
+applications.",2203.03841v1
+2022-04-20,Ferroelectricity and topological vortices from molecular ordering in metal-organic frameworks,"Metal-organic frameworks comprehend a wide class of hybrid organic-inorganic
+materials with general structure A$_m$BX$_n$, with $A$ and $X$ being organic
+molecules and B a metal cation. This often results in enhanced structural
+flexibility and new functionalities. Hybrid perovskites ABX$_3$ are a
+well-known example.} In an Iron-based perovskites, (DMA)Fe^{II-III}(COOH)_3,
+dimethylammonium (DMA) molecules are organized in a hexagonal structure. They
+are orientationally disordered at high temperatures, but order at around
+$T=100$~K in a peculiar toroidal pattern. Recent experimental and theoretical
+study suggest the appearance of ferroelectric polarization in this phase,
+although the measured polarization is small, and the mechanism of
+ferroelectricity is still debated. We formulate a Landau-type theory that
+clarifies the connection between the electric polarization, molecular pattern,
+and distortive modes of the inorganic lattice. We find a remarkable mechanism
+of improper ferroelectricity, analogue to the trimerization process in
+inorganic hexagonal ferrites and manganites, but here driven by the ordering of
+organic molecules in a metal-organic framework. Our study reveals an extremely
+rich phase diagram with the prediction of topological domain walls, where the
+ferroelectricity arise from tripling the unit cells due to molecular ordering.
+Wide domain walls with inner structure are predicted.",2204.09546v1
+2022-06-21,An iterative method for reference pattern selection in high resolution electron backscatter diffraction (HR-EBSD),"For high (angular) resolution electron backscatter diffraction (HR-EBSD), the
+selection of a reference diffraction pattern (EBSP0) significantly affects the
+precision of the calculated strain and rotation maps. This effect was
+demonstrated in plastically deformed body-centred cubic and face-centred cubic
+ductile metals (ferrite and austenite grains in duplex stainless steel) and
+brittle single-crystal silicon, which showed that the effect is not only
+limited to measurement magnitude but also spatial distribution. An empirical
+relationship was then identified between the cross-correlation parameter and
+angular error, which was used in an iterative algorithm to identify the optimal
+reference pattern that maximises the precision of HR-EBSD.",2206.10242v2
+2022-12-13,Logarithmic wave-mechanical effects in polycrystalline metals: Theory and experiment,"Schrodinger-type wave equations with logarithmic nonlinearity occur in
+hydrodynamic models of Korteweg-type materials with capillarity and surface
+tension, which can undergo liquid-solid or liquid-gas phase transitions. One of
+the predictions of the theory is a periodic pattern of density inhomogeneities
+occurring in the form of either bubbles (topological phase), or cells
+(non-topological phase). Such inhomogeneities are described by solitonic
+solutions of a logarithmic wave equation, gaussons and kinks, in the vicinity
+of the liquid-solid phase transition. During the solidification process, these
+inhomogeneities become centers of nucleation, thus shaping the polycrystalline
+structure of the metal grains. The theory predicts a Gaussian profile of
+material density inside such a cell, which should manifest in a Gaussian-like
+profile of microhardness inside a grain. We report experimental evidence of
+large-scale periodicity in the structure of grains in the ferrite steel
+S235/A570, copper C-Cu/C14200, austenite in steel X10CrNiTi18-10/AISI 321, and
+aluminium-magnesium alloy 5083/5056; and also Gaussian-like profiles of
+microhardness inside an averaged grain in these materials.",2212.06407v1
+2023-01-04,Diameter and Aggregation Controlled Preparation by Solvothermal Synthesis of Ultra-small Particles CuFe$_2$O$_4$,"Copper ferrite nanoparticles have catalytic activity for hydrogen peroxide,
+which can be used in many fields. This characteristic comes from the physical
+properties of matters at nanometer scale. Thus, controlling the size and
+aggregation of nanoparticles during the synthesis is one of the ways to obtain
+target performance. In this article, a kind of ultra-small nano particle
+CuFe$_2$O$_4$ with uniform morphology was prepared by solvothermal synthesis.
+The effects of solvent, reactant molar ratio, reaction temperature, surfactant
+and reaction time on the yield of CuFe$_2$O$_4$, size and morphology of nano
+particles were investigated under different synthesis conditions. XRD, TEM, EDS
+were used to analysis the materials, and the physical properties of the
+products were analyzed. An optimized solvothermal synthesis scheme was
+proposed.",2301.01658v2
+2023-01-21,Hard Ferromagnets as a New Perspective on Materials for Thermomagnetic Power Generation Cycles,"We consider the ways in which magnetically hard materials can be used as the
+working materials in thermomagnetic power generation (TMG) cycles in order to
+expand the area in the magnetisation vs. applied field ($M-H$) plane available
+for energy conversion. There are 3 parts to this Perspective. First,
+experiments on commercially available hard ferrites reveal that, while these
+materials are not yet good TMG candidates, hard ferromagnets with higher
+thermal conductivity and a greater change of magnetization with temperature
+could outperform existing TMG materials. Second, computational results indicate
+that biasing a soft magnet with a hard ferromagnet is essentially equivalent to
+shifting the $M-H$ loop by an amount proportional to the field of the biasing
+magnet. Work outputs under biased conditions show a substantial improvement
+over unbiased cycles, but experimental verification is needed. Third, we
+discuss the rationale for exploring artificial spin reorientation materials as
+novel TMG working materials.",2301.08854v1
+2023-01-21,Investigation the effect of pH and reducing agent concentration on the structural properties of zinc-substitution magnetite nanoparticles,"Today, spinel ferrite nanoparticles are widely used in the medical field for
+cancer treatment, drug delivery, and magnetic resonance imaging contrast agent
+due to their superior magnetic properties and biocompatibility. Due to the
+strong dependence of magnetic properties on morphology and other structural
+aspects, the magnetic properties of these nanoparticles depend on their
+manufacturing process. One of the goals of the researchers is to improve the
+magnetic properties of these nanoparticles by substituting elements such as
+manganese, cobalt, zinc, nickel, magnesium and iron. In this research, first,
+magnetic Zn0.3Fe0.6O4 nanoparticles were synthesized by hydrothermal method in
+the presence of citric acid as a reducing agent. In order to reduce the amount
+of impurity and obtain the pure spinel phase and reduce the size of magnetic
+nanoparticles, the hydrothermal process was carried out in the presence of
+different concentrations of the reducing agent and pH level of the medium. The
+structural investigations of the resulting nanoparticles were carried out by
+X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results
+showed that in order to obtain pure and single-phase spinel nanoparticles with
+appropriate particle size and size distribution, it is necessary to control the
+concentration of reducing agent and pH.",2302.10168v1
+2023-05-22,Experimental test of the Rosenzweig-Porter model for the transition from Poisson to Gaussian unitary ensemble statistics,"We report on an experimental investigation of the transition of a quantum
+system with integrable classical dynamics to one with violated time-reversal
+(T) invariance and chaotic classical counterpart. High-precision experiments
+are performed with a flat superconducting microwave resonator with circular
+shape in which T-invariance violation and chaoticity are induced by magnetizing
+a ferrite disk placed at its center, which above the cutoff frequency of the
+first transverse-electric mode acts as a random potential. We determine a
+complete sequence of approx. 1000 eigenfrequencies and find good agreement with
+analytical predictions for the spectral properties of the Rosenzweig-Porter
+(RP) model, which interpolates between Poisson statistics expected for typical
+integrable systems and Gaussian unitary ensemble statistics predicted for
+chaotic systems with violated T invariance. Furthermore, we combine the RP
+model and the Heidelberg approach for quantum-chaotic scattering to construct a
+random-matrix model for the scattering (S) matrix of the corresponding open
+quantum system and show that it perfectly reproduces the fluctuation properties
+of the measured S matrix of the microwave resonator.",2305.12840v3
+2023-05-24,Enhancement of synthetic magnetic field induced nonreciprocity via bound states in continuum in dissipatively coupled systems,"The nonreciprocal propagation of light typically requires use of materials
+like ferrites or magneto-optical media with a strong magnetic bias or methods
+based on material nonlinearities which require use of strong electromagnetic
+fields. A simpler possibility to produce nonreciprocity is to use
+spatio-temporal modulations to produce magnetic fields in synthetic dimensions.
+In this paper we show that dissipatively coupled systems can lead to
+considerable enhancement of nonreciprocity in synthetic fields. The enhancement
+comes about from the existence of nearly nondecaying mode -bound state in
+continuum (BIC) in dissipatively coupled systems. The dissipative coupling
+occurs in a wide class of systems coupled via transmission lines, waveguides,
+or nano fibers. The systems could be optical resonators or microscopic qubits.
+Remarkably we find that for specific choice of the modulation amplitudes, the
+transmission say in forward direction is completely extinguished whereas in the
+backward direction it becomes maximum. The synthetic fields produce
+transmission resonances which show significant line narrowing which owe their
+origin to existence of BIC's in dissipative systems.",2305.14945v1
+2023-06-19,Extreme nonreciprocity in metasurfaces based on bound states in the continuum,"Nonreciprocal devices, including optical isolators, phase shifters, and
+amplifiers, are pivotal for advanced optical systems. However, exploiting
+natural materials is challenging due to their weak magneto-optical effects,
+requiring substantial thickness to construct effective optical devices. In this
+study, we demonstrate that subwavelength metasurfaces supporting bound states
+in the continuum and made of conventional magnetic ferrite can exhibit extreme
+nonreciprocity in the Faraday configuration and near-unity magnetic circular
+dichroism. These metasurfaces enhance the magneto-optical effect by 3--4 orders
+of magnitude compared to a continuous film of the same material. This
+significant enhancement is achieved by leveraging Huygens' condition in the
+metasurface whose structural units support paired electric and magnetic dipole
+resonances. We develop the multi-mode temporal coupled-mode theory for the
+observed enhancement of the magneto-optical effect and confirm our findings
+with the full-wave simulations.",2306.10827v1
+2023-06-26,Dispersion of Multiferroic Nanoparticles in a Bent-Core Nematic Liquid Crystal: Experimental and Theoretical Study,"A novel nanocomposite system has been prepared by dispersing multiferroic
+bismuth ferrite nanoparticles (BiFeO$_3$) in a bent-core nematic liquid crystal
+(8-F-OH) that exhibits cybotactic clusters. Transition temperature, optical
+textures, order parameter $S_m$, and dielectric spectroscopy experiments are
+performed in the doped system, and the results are compared with the pure one.
+The main experimental outcome is that the doped system has increased
+orientational order parameters, even though the cybotactic cluster size is
+reduced due to the incorporation of multiferroic BiFeO$_3$ nanoparticles. The
+transition temperature, as observed under polarising optical microscopy,
+clearly indicates a reduction of $1 - 2~ ^\circ{\rm C}$ in the doped system
+compared to the pure one, and we conjecture this is due to the disordering of
+the cybotactic cluster in the doped system. Based on the experimental findings,
+a Landau-de Gennes-type free energy model is developed. The model qualitatively
+explains the increased mean order parameter and the disordering of cybotactic
+clusters with increasing polarization value of nanoparticles. This is
+corroborated by experimental findings.",2306.14623v2
+2023-06-29,Analytical approximations for magnetic coupling coefficients between adjacent coils,"This paper presents a simple yet novel two-dimensional modelling approach for
+approximating the coupling coefficient between neighbouring inductors as a
+function of co-planar separation and relative angular displacement. The
+approach employs simple geometric arguments to predict the effective magnetic
+flux between inductors. Two extreme coil geometry regimes are considered;
+planar coils (i.e. on printed circuit board), and solenoid coils, each with
+asymmetric ferrite cores about the central magnetic plane of the inductor. The
+proposed geometric approximation is used to predict the coupling coefficient
+between sensors as a function of separation distance and angular displacement
+and the results are validated against two-dimensional finite element modelling
+results. The analytical approximations show excellent agreement with the FE
+analysis, predicting comparable trends with changing separation and angular
+displacement, enabling best fitting to 2D FE and 3D numerical data with a
+residual standard deviation of less than 0.5\% for the planar coil
+approximation. The work demonstrates the validity of the analytical
+approximation for predicting coupling behaviour between neighbouring coils.
+This has practical uses for the automated estimation of the physical separation
+between coils, or the curvature of surfaces they are rested or adhered to.",2306.16745v2
+2023-07-03,Magnetic lump motion in saturated ferromagnetic films,"In this paper, we study in detail the nonlinear propagation of magnetic
+soliton in a ferromagnetic film. The sample is magnetized to saturation by an
+external field perpendicular to film plane. A new generalized (2+1)-dimensional
+short-wave asymptotic model is derived. The bilinear-like forms of this
+equation are constructed, and exact magnetic line soliton solutions are
+exhibited. It is observed that a series of stable lumps can be generated by an
+unstable magnetic soliton under Gaussian disturbance. Such magnetic lumps are
+highly stable and can maintain their shapes and velocities during evolution or
+collision. The interaction between lump and magnetic soliton, as well as
+interaction between two lumps, are numerically investigated. We further discuss
+the nonlinear motion of lumps in ferrites with Gilbert-damping and
+inhomogeneous exchange effects. The results show that the Gilbert-damping
+effects make the amplitude and velocity of the magnetic lump decay
+exponentially during propagation. And the shock waves are generated from a lump
+when quenching the strength of inhomogeneous exchange.",2307.00903v1
+2023-07-18,Room-temperature magnetism and controlled cation distribution in vanadium ferrite thin films,"Spinel oxides demonstrate significant technological promise due to the vast
+array of interrelated physical properties that their unique structure supports.
+Specifically, the Fe1+xV2-xO4 spinel system garners extensive interest due to
+the presence of orbitally ordered states and multiferroism. This study focuses
+on the elaboration of high-quality Fe2VO4 (x = 1) thin films on MgO substrates
+via pulsed laser deposition. Structural analyses confirm the epitaxial growth
+of the films, their high crystallinity and fully strained nature. The cationic
+distribution and stoichiometry were investigated using Resonant Elastic X-ray
+Scattering experiments, in conjunction with comprehensive characterization of
+the films' physical and electrical properties. The films exhibit
+room-temperature magnetism, with a magnetization consistent with the
+(Fe3+)Td[Fe2+V3+2]OhO4 inverse spinel structure unveiled by anomalous
+diffraction. This work represents the inaugural successful deposition of Fe2VO4
+thin films, thereby expanding the family of spinel vanadium oxide thin films
+with a new member that demonstrates room-temperature magnetic properties.",2307.09598v1
+2023-09-20,Construction of the Initial Part of a Ion Linear Accelerator from Similar Short Cavities,"The construction of the initial part of a normally conducting linac for
+hydrogen ion beams with a pulsed current of ~20 mA up to an energy of ~70 MeV
+is considered. The RFQ at a frequency of ~160 MHz accelerates ions to an energy
+of ~4 MeV. Further acceleration is carried out at a doubled frequency by short,
+up to $5\beta\lambda$, cavities, operating in the TM010 mode, with drift tubes.
+Focusing is carried out by doublets of quadrupole lenses placed between the
+cavities. The structure of the accelerating-focusing channel, with given beam
+parameters, with reserves provides both the conditions for stable longitudinal
+and transverse motion of particles, and reliable technical implementation. The
+main results of the simulations of particle dynamics and the main parameters of
+the elements of the channel are presented. The possibility of constructing an
+linac with a higher output energy is analyzed.",2309.11431v1
+2023-09-24,Effect of organic solvent on the cold sintering processing of SrFe12O19 platelet-based permanent magnets,"In this work we have investigated the effect of the solvent during the
+processing of SrFe12O19 platelet-based permanent magnets by cold sintering
+process (CSP) plus a post-thermal treatment. Several organic solvents: glacial
+acetic acid, oleic acid and oleylamine have been analyzed, optimizing the CSP
+temperatures at 190-270 {\deg}C, under pressures of 375-670 MPa and 6-50 wt% of
+solvent. Modifications in the morphological and structural properties are
+identified depending on the solvent, which impacts on the magnetic response.
+Independently of the solvent, the mechanical integrity of ferrite magnets
+obtained by CSP is improved by a post-annealing at 1100 {\deg}C for 2 h,
+resulting in relative densities around 92 % with an average grain size of 1
+{\mu}m and a fraction of SrFe12O19 phase > 91 %. Hc > 2.1 kOe and MS of 73
+emu/g are obtained in the final sintered ceramic magnets, exhibiting the
+highest HC value of 2.8 kOe for the magnet sintered using glacial acetic acid.",2309.15859v1
+2023-10-06,Fast Output Energy Regulation in a Medical Proton Linac,"In proton therapy, depth scanning of the irradiated object is performed by
+changing the Output Energy (OE) of the accelerated beam. In pulsed linear
+accelerators, adjustment of the OE is usually by changing the amplitude and/or
+phase of the field in the accelerating elements from one RF pulse to another.
+The application of non-inertial traveling wave accelerating sections makes it
+possible to change quickly the phase of the accelerating field during the RF
+pulse. The phase of the field in the constant gradient section is determined
+both by the phase of the input RF signal and by the process of wave propagation
+in the dispersive structure. The calculation results of the traveling wave
+propagation in the accelerating structure when the phase of the input RF signal
+changes and the results of simulation the dynamics of particles confirm the
+change in the linac's OE during the RF pulse. The proposed method for
+regulation the OE makes it possible to increase in orders the speed of scanning
+the irradiated object by depth.",2310.04262v1
+2023-10-23,Design of the LLRF control system for MA cavity at CSNS RCS,"The China Spallation Neutron Source (CSNS) beam power was successfully
+reached 125 kW with a low beam loss in February 2022. In order to increase beam
+power, during the summer in 2022, we employ magnetic-alloy (MA) cavity in the
+rapid cycling synchrotron (RCS). It is a wideband cavity (Q=2), allows the
+second harmonic rf (h= 4) operation, with the existing ferrite cavity to
+realize the dual-harmonic acceleration. The second harmonic (h=4) is used for
+the bunch shape control and alleviating the space charge effects. We design of
+the low-level RF(LLRF) control system for MA cavity, in this paper, we describe
+the system design and implementation, and the preliminary test results.",2310.14915v1
+2023-11-16,Persistent anisotropy of the spin cycloid in BiFeO3 through ferroelectric switching,"A key challenge in antiferromagnetic spintronics is the control of spin
+configuration on nanometer scales applicable to solid-state technologies.
+Bismuth ferrite (BiFeO3) is a multiferroic material that exhibits both
+ferroelectricity and canted antiferromagnetism at room temperature, making it a
+unique candidate in the development of electric-field controllable magnetic
+devices. The magnetic moments in BiFeO3 are arranged into a spin cycloid,
+resulting in unique magnetic properties which are tied to the ferroelectric
+order. Previous understanding of this coupling has relied on average, mesoscale
+measurements to infer behavior. Using nitrogen vacancy-based diamond
+magnetometry, we show that the spin cycloid can be deterministically controlled
+with an electric field. The energy landscape of the cycloid is shaped by both
+the ferroelectric degree of freedom and strain-induced anisotropy, restricting
+the magnetization changes to specific ferroelectric switching events. This
+study provides understanding of the antiferromagnetic texture in BiFeO3 and
+paves new avenues for designing magnetic textures and spintronic devices.",2311.10169v1
+2023-12-14,Confinement of electron holes via the peroxo group formation in the negative charge-transfer materials on the example of SrFeO3: plane-wave density functional theory predictions,"The present work puts forward a concept that the thermostable O1s XPS peaks
+with energy of about 531 eV in negative charge-transfer SrFeO_{3-\delta}
+perovskite are determined by the peroxo-like oxygen species. The peroxo group
+forms via coupling two oxygen anions coordinated to iron cations with
+d^5\bar-under{L} (\bar-under{L}-oxygen electron hole) configuration. By means
+of plane-wave DFT+U approach there have been shown that the peroxo group
+represents a metastable state in the absence of oxygen vacancies nearby. The
+O-O bonding confines two electron holes freezing the 3+ oxidation state for two
+iron cations bridged by peroxide. Increasing the peroxo group numbers makes the
+ferrite a semiconductor with charge-transfer gap of about 0.6 eV.",2312.08665v1
+2024-01-11,A first-principles study of Zn induced liquid metal embrittlement at bcc and fcc grain boundaries,"Zn induced liquid metal embrittlement (LME) is a major concern in particular
+for advanced high strength steels, which often contain a significant amount of
+austenite compared to established steel grades. Using density functional theory
+(DFT) calculations we, therefore, compare the behaviour of Zn in ferrite (bcc)
+and austenite (fcc) grain boundaries (GBs) with different magnetic ordering to
+investigate the role of crystal structure as well as magnetism in LME. We
+address the performance of DFT based paramagnetic calculations by utilizing the
+spin space averaging relaxation approach. Our results show that both magnetic
+and elastic contributions have significant influence towards segregation and
+embrittling behaviour of Zn. The primary requirement is the elastic
+contribution, while the presence of magnetic disorder increases the critical
+concentrations for the onset of GB weakening. While Zn segregation is more
+favourable in bcc compared to fcc GB, larger impact of Zn coverage on GB
+weakening is observed for fcc. For both structures, the rapid decrease in
+surface defect state energies is identified as the driving force behind GB
+weakening. These surface defect states stabilize at lower Zn concentrations
+than GB defect states.",2401.05997v1
+2024-02-22,Barium hexaferrite-based nanocomposites as Random Magnets for microwave absorption H,"The present work reports experimental evidence of random magnetic behavior
+observed in modified barium hexagonal ferrites. A significant transition in the
+magnetic properties of this system is observed when divalent cations (Ni2+,
+Cu2+, Mn2+) are introduced in the structure and give rise to a magnetic
+nanocomposite. Such introduction takes place in a random manner throughout each
+sample and creates the conditions for such materials to behave as random
+magnets. We verify the occurrence of such behavior in our samples by fitting
+the magnetization in approaching saturation to the corresponding theoretical
+model. We therefore analyze the microwave absorption capacities of random
+magnets in the GHz range and predict large and broad absorption signals under
+certain conditions. The findings presented here postulate, for the first time,
+ceramic materials as promising random magnets and underline their potential as
+microwave absorbers, in good agreement with recent theoretical models.",2402.14324v1
+2006-11-20,Cationic exchange in nanosized ZnFe2O4 spinel revealed by experimental and simulated near-edge absorption structure,"The non-equilibrium cation site occupancy in nanosized zinc ferrites (6-13
+nm) with different degree of inversion (0.2 to 0.4) was investigated using Fe
+and Zn K-edge x-ray absorption spectroscopy XANES and EXAFS, and magnetic
+measurements. The very good agreement between experimental and ab-initio
+calculations on the Zn K-edge XANES region clearly show the large
+Zn2+(A)--Zn2+[B] transference that takes place in addition to the
+well-identified Fe3+[B]--Fe3+(A) one, without altering the long-range
+structural order. XANES spectra features as a function of the spinel inversion
+were shown to depend on the configuration of the ligand shells surrounding the
+absorbing atom. This XANES approach provides a direct way to sense cationic
+inversion in these spinel compounds. We also demonstrated that a mechanical
+crystallization takes place on nanocrystalline spinel that causes an increase
+of both grain and magnetic sizes and, simultaneously, generates a significant
+augment of the inversion.",0611532v2
+2005-02-03,Spacetime Deformations and Electromagnetism in Material Media,"This paper is intended to investigate the relation between electrodynamics in
+anisotropic material media and its analogous formulation in an spacetime, with
+non-null Riemann curvature tensor. After discussing the electromagnetism via
+chiral differential forms, we point out the optical activity of a given
+material medium, closely related to topological spin, and the Faraday rotation,
+associated to topological torsion. Both quantities are defined in terms of the
+magnetic potential and the electric and magnetic fields and excitations. We
+revisit some properties of material media and the associated Green dyadics.
+Some related features of ferrite are also investigated. It is well-known that
+the constitutive tensor is essentially equivalent to the Riemann curvature
+tensor. In order to investigate the propagation of electromagnetic waves in
+material media, we prove that it is analogous to consider the electromagnetic
+wave propagation in the vacuum, but this time in a curved spacetime, which is
+obtained by a deformation of the lorenztian metric of Minkowski spacetime.
+Spacetime deformations leave invariant the form of Maxwell equations. Also,
+there exists a close relation between Maxwell equations in curved spacetime and
+in an anisotropic material medium, indicating that electromagnetism and
+spacetime properties are deeply related. Besides, the geometrical aspects of
+wave propagation can be described by an effective geometry which represents a
+deformation of the lorentzian metric of Minkowski spacetime.",0502012v4
+2005-03-01,Advanced bridge (interferometric) phase and amplitude noise measurements,"The measurement of the close-to-the-carrier noise of rf and microwave devices
+is a relevant issue in time and frequency metrology and in some fields of
+electronics, physics and optics. While phase noise is the main concern,
+amplitude noise is often of interest. The highest sensitivity is achieved with
+the bridge (interferometric) method, which consists of the amplification and
+synchronous detection of the noise sidebands after suppressing the carrier by
+vector subtraction of an equal signal. A substantial progress in understanding
+the flicker noise mechanism of the interferometer results in new schemes that
+improve by 20--30 dB the sensitivity at low Fourier frequencies.
+  The article provides the complete theory and detailed design criteria, and
+reports on the implementation of a prototype. In real-time measurements, a
+background noise of -175 -180 dBrad^2/Hz has been obtained at f=1 Hz off the
+100 MHz carrier. Exploiting correlation and averaging in similar conditions,
+the sensitivity exceeds -185 dBrad^2/Hz at f=1 Hz. A residual noise of -203
+dBrad^2/Hz at f=250 Hz off the carrier has been obtained, while the ultimate
+noise floor is still limited by the averaging capability of the correlator.
+This is equivalent to a S/N ratio of 2E20 with a frequency spacing of 2.5E-6.
+  Applications include the measurement of the properties of materials and the
+observation of weak flicker-type physical phenomena, out of reach for other
+instruments. We measured the flicker noise of a by-step attenuator (-171
+dB[rad^2]/Hz at f=1 Hz) and of the ferrite noise of a reactive power divider
+(-173.7 dB[rad^2]/Hz at f=1 Hz) without need of correlation.",0503015v1
+2006-01-24,Trapping atoms on a transparent permanent-magnet atom chip,"We describe experiments on trapping of atoms in microscopic magneto-optical
+traps on an optically transparent permanent-magnet atom chip. The chip is made
+of magnetically hard ferrite-garnet material deposited on a dielectric
+substrate. The confining magnetic fields are produced by miniature magnetized
+patterns recorded in the film by magneto-optical techniques. We trap Rb atoms
+on these structures by applying three crossed pairs of counter-propagating
+laser beams in the conventional magneto-optical trapping (MOT) geometry. We
+demonstrate the flexibility of the concept in creation and in-situ modification
+of the trapping geometries through several experiments.",0601163v2
+2007-06-19,Synthesis and magnetic properties of NiFe_{2-x}Al_{x}O_{4} nanoparticles,"Nanocrystalline Al-doped nickel ferrite powders have been synthesized by
+sol-gel auto-ignition method and the effect of non-magnetic aluminum content on
+the structural and magnetic properties has been studied. The X-ray diffraction
+(XRD) revealed that the powders obtained are single phase with inverse spinel
+structure. The calculated grain sizes from XRD data have been verified using
+transmission electron microscopy (TEM). TEM photographs show that the powders
+consist of nanometer-sized grains. It was observed that the characteristic
+grain size decreases from 29 to 6 nm as the non-magnetic Al content increases,
+which was attributed to the influence of non-magnetic Al concentration on the
+grain size. Magnetic hysteresis loops were measured at room temperature with a
+maximum applied magnetic field of 1T. As aluminum content increases, the
+measured magnetic hysteresis curves become more and more narrow and the
+saturation magnetization and remanent magnetization both decreased. The
+reduction of agnetization compared to bulk is a consequence of spin
+non-collinearity. Further reduction of magnetization with increase of aluminum
+content is caused by non-magnetic Al^{3+} ions and weakened interaction between
+sublattices. This, as well as the decrease in hysteresis was understood in
+terms of the decrease in particle size.",0706.2794v1
+2008-06-12,"Comment on ""Ferroelectrically Induced Weak Ferromagnetism by Design"", C. Fennie, PRL 100, 167203 (2008)","The question of how ferroelectric polarization is coupled to magnetism in
+magnetoelectric multiferroics, in which both types of order are simultaneously
+present, is of considerable scientific and practical interest. A recent Letter
+\cite{fennie} presents an analysis of the important ``ABO$_3$'' class of
+perovskite multiferroics. This Letter argues that antiferromagnetic
+multiferroics with magnetic ions on the B site, such as the well-studied
+room-temperature multiferroic bismuth ferrite (A=Bi, B=Fe), cannot show linear
+magnetoelectric coupling of the form ${\bf P} \cdot ({\bf L} \times {\bf M})$.
+Here ${\bf P}$ is polarization and ${\bf L}$ and ${\bf M}$ are
+antiferromagnetic and ferromagnetic moments. The conclusion of Ref.
+\onlinecite{fennie} is that only materials with magnetic A-site have this
+coupling. This Comment presents a compact analysis of magnetoelectric coupling
+in the ABO$_3$ multiferroics. We show that the argument of Ref.
+\onlinecite{fennie} does forbid $E_{PLM}$ if the final low-symmetry phase
+contains only one distortion that, like ${\bf P}$, breaks all inversion
+symmetries. In reality, there are multiple distortions in this symmetry class,
+and cross-terms generate $E_{PLM}$. Our analysis gives simple conclusions about
+existence and optimization of magnetoelectric coupling in ABO$_3$ materials.",0806.2142v4
+2009-07-21,Ferromagnetic transition metal implanted ZnO: a diluted magnetic semiconductor?,"Recently theoretical works predict that some semiconductors (e.g. ZnO) doped
+with magnetic ions are diluted magnetic semiconductors (DMS). In DMS magnetic
+ions substitute cation sites of the host semiconductor and are coupled by free
+carriers resulting in ferromagnetism. One of the main obstacles in creating DMS
+materials is the formation of secondary phases because of the solid-solubility
+limit of magnetic ions in semiconductor host. In our study transition metal
+ions were implanted into ZnO single crystals with the peak concentrations of
+0.5-10 at.%. We established a correlation between structural and magnetic
+properties. By synchrotron radiation X-ray diffraction (XRD) secondary phases
+(Fe, Ni, Co and ferrite nanocrystals) were observed and have been identified as
+the source for ferromagnetism. Due to their different crystallographic
+orientation with respect to the host crystal these nanocrystals in some cases
+are very difficult to be detected by a simple Bragg-Brentano scan. This results
+in the pitfall of using XRD to exclude secondary phase formation in DMS
+materials. For comparison, the solubility of Co diluted in ZnO films ranges
+between 10 and 40 at.% using different growth conditions pulsed laser
+deposition. Such diluted, Co-doped ZnO films show paramagnetic behaviour.
+However, only the magnetoresistance of Co-doped ZnO films reveals possible s-d
+exchange interaction as compared to Co-implanted ZnO single crystals.",0907.3536v1
+2010-01-12,Phonon Spectroscopy Near Phase Transition Temperatures in Multferroic BiFeO3 Epitaxial Thin Films,"We report a Raman scattering investigation of multiferroic bismuth ferrite
+BiFeO3 epitaxial (c-axis oriented) thin films from -192 to 1000C. Phonon
+anomalies have been observed in three temperature regions: in the gamma-phase
+from 930C to 950C; at ~370C, Neel temperature (TN), and at ~123C, due to a
+phase transition of unknown type (magnetic or structural). An attempt has been
+made to understand the origin of the weak phonon-magnon coupling and the
+dynamics of the phase sequence. The disappearance of several Raman modes at
+~820C (Tc) is compatible with the known structural phase transition and the
+Pbnm orthoferrite space group assigned by Arnold {\it et al.} \cite{arnold:09}.
+The spectra also revealed a {\it non-cubic} $\beta$-phase from 820-930\dc and
+the same {\it non-cubic} phase extends through the $\gamma$-phase between
+930-950\dc, in agreement with Arnold {\it et al.} \cite{arnold2:09}, and an
+evidence of a cubic $\delta$-phase around 1000\dc in thin films that is not
+stable in powder and bulk. Such a cubic phase has been theoretically predicted
+in \cite{vasquez:prb09}. Micro-Raman scattering and X-ray diffraction showed no
+structural decomposition in thin films during the thermal cycling from
+22-1000\dc.",1001.1997v1
+2010-12-16,Coupled states of electromagnetic fields with magnetic-dipolar-mode vortices: MDM-vortex polaritons,"Under the influence of the material environment, electromagnetic fields in
+the near-field regime exhibit quite different nature from those in the
+far-field free space. A coupled state of an electromagnetic field with an
+electric or magnetic dipole-carrying excitation is well known as a polariton.
+Such a state is the result of the mixing of a photon with an excitation of a
+material. The most discussed types of polaritons are phonon-polaritons,
+exciton-polaritons, and surface plasmon-polaritons. Recently, it was shown that
+in microwaves strong magnon-photon coupling can be achieved due to
+magnetic-dipolar-mode (MDM) vortices in small thin-film ferrite disks. These
+coupled states can be specified as MDM-vortex polaritons. In this paper we
+study properties of MDM-vortex polaritons. We show that MDM-vortex polaritons
+are characterized by helicity behaviors. For the observed frequency splits of
+MDM resonances there are different-type helicities. In the split-resonance
+states one has or localization, or cloaking of electromagnetic fields. We
+analyze numerically a variety of the field topological structures of MDM-vortex
+polaritons and give theoretical insights into the possible origin of such
+topologically distinctive states. The shown properties of MDM-vortex polaritons
+can be useful for realization of novel microwave metamaterial structures and
+near-field sensing applications.",1012.3621v1
+2011-03-05,Physics and measurements of magnetic materials,"Magnetic materials, both hard and soft, are used extensively in several
+components of particle accelerators. Magnetically soft iron-nickel alloys are
+used as shields for the vacuum chambers of accelerator injection and extraction
+septa; Fe-based material is widely employed for cores of accelerator and
+experiment magnets; soft spinel ferrites are used in collimators to damp
+trapped modes; innovative materials such as amorphous or nanocrystalline core
+materials are envisaged in transformers for high-frequency polyphase resonant
+convertors for application to the International Linear Collider (ILC). In the
+field of fusion, for induction cores of the linac of heavy-ion inertial fusion
+energy accelerators, based on induction accelerators requiring some 107 kg of
+magnetic materials, nanocrystalline materials would show the best performance
+in terms of core losses for magnetization rates as high as 105 T/s to 107 T/s.
+After a review of the magnetic properties of materials and the different types
+of magnetic behaviour, this paper deals with metallurgical aspects of
+magnetism. The influence of the metallurgy and metalworking processes of
+materials on their microstructure and magnetic properties is studied for
+different categories of soft magnetic materials relevant for accelerator
+technology. Their metallurgy is extensively treated. Innovative materials such
+as iron powder core materials, amorphous and nanocrystalline materials are also
+studied. A section considers the measurement, both destructive and
+non-destructive, of magnetic properties. Finally, a section discusses magnetic
+lag effects.",1103.1069v1
+2012-08-27,Piezoelectric nonlinearity and frequency dispersion of the direct piezoelectric response of BiFeO3 ceramics,"We report on the frequency and stress dependence of the direct piezoelectric
+d33 coefficient in BiFeO3 ceramics. The measurements reveal considerable
+piezoelectric nonlinearity, i.e., dependence of d33 on the amplitude of the
+dynamic stress. The nonlinear response suggests a large irreversible
+contribution of non-180{\deg} domain walls to the piezoelectric response of the
+ferrite, which, at present measurement conditions, reached a maximum of 38% of
+the total measured d33. In agreement with this interpretation, both types of
+non-180{\deg} domain walls, characteristic for the rhombohedral BiFeO3, i.e.,
+71{\deg} and 109{\deg}, were identified in the poled ceramics using
+transmission electron microscopy (TEM). In support to the link between
+nonlinearity and non-180{\deg} domain wall contribution, we found a correlation
+between nonlinearity and processes leading to deppining of domain walls from
+defects, such as quenching from above the Curie temperature and
+high-temperature sintering. In addition, the nonlinear piezoelectric response
+of BiFeO3 showed a frequency dependence that is qualitatively different from
+that measured in other nonlinear ferroelectric ceramics, such as ""soft""
+(donor-doped) Pb(Zr,Ti)O3 (PZT); possible origins of this dispersion are
+discussed. Finally, we show that, once released from pinning centers, the
+domain walls can contribute extensively to the electromechanical response of
+BiFeO3; in fact, the extrinsic domain-wall contribution is relatively as large
+as in Pb-based ferroelectric ceramics with morphotropic phase boundary (MPB)
+composition, such as PZT. This finding might be important in the search of new
+lead-free MPB compositions based on BiFeO3 as it suggests that such
+compositions might also exhibit large extrinsic domain-wall contribution to the
+piezoelectric response.",1208.5426v1
+2012-12-06,Theoretical and numerical study of lamellar eutectoid growth influenced by volume diffusion,"We investigate the lamellar growth of pearlite at the expense of austenite
+during the eutectoid transformation in steel. To begin with, we extend the
+Jackson-Hunt-type calculation (previously used to analyze eutectic
+transformation) to eutectoid transformation by accounting for diffusion in all
+the phases. Our principal finding is that the growth rates in presence of
+diffusion in all the phases is different as compared to the case when diffusion
+in growing phases is absent. The difference in the dynamics is described by a
+factor '{\rho}' which comprises of the ratio of the diffusivities of the bulk
+and the growing phases, along with the ratios of the slopes of the phase
+co-existence lines. Thereafter, we perform phase-field simulations, the results
+of which are in agreement with analytical predictions. The phase-field
+simulations also reveal that diffusion in austenite as well as ferrite leads to
+the formation of tapered cementite along with an overall increase in the
+transformation kinetics as compared to diffusion in austenite (only). Finally,
+it is worth noting that the aim of present work is not to consider the
+pearlitic transformation in totality, rather it is to isolate and thereby
+investigate the influence of diffusivity in the growing phases on the front
+velocity.",1212.1250v4
+2012-12-12,Ferrimagnetism and spin canting of ZnFe2O4 nanoparticles embedded in ZnO matrix,"The structural and magnetic properties of ZnFe2O4 nanoparticles embedded in a
+non-magnetic ZnO matrix are presented. X-ray diffractograms and Transmission
+Electron Microscopy (TEM) images showed that the resulting samples are composed
+of crystalline ferrite nanoparticles with average crystallite size <D> =
+23.4(0.9) nm, uniformly dispersed within the ZnO matrix. Magnetization data
+indicated a superparamagnetic-like behavior from room temperature down to T_{M}
+~ 20 K, where a transition to a frozen state is observed. The M(H) curves
+displayed nearly zero coercive field down to TM, where a sharp increase in the
+H_C value is observed. The measured saturation magnetization M_S values at 200
+and 2 K were M_S = 0.028(3) and 0.134(7) muB/f.u. ZnFe2O4 respectively, showing
+the existence of small amounts of non compensated atomic moments. M\""ossbauer
+measurements at low temperatures confirmed the transition to a magnetically
+ordered state for T < 25 K, where two magnetically split sextets develop.
+Whereas these two sextets show strong overlap due to the similar hyperfine
+fields, in-field M\""ossbauer spectra clearly showed two different Fe3+ sites,
+demonstrating that the sample is ferrimagnetically ordered. The two spinel
+sites are found to behave differently under an external field of 12 T: whereas
+the moments located at A sites show a perfect alignment with the external
+field, spins at B sites are canted by an angle alpha_B = 49(2){\deg}. We
+discuss the significance of this particle structure for the observed magnetic
+behavior.",1212.2798v1
+2013-03-12,Démixtion et ségrégation superficielle dans les alliages fer-chrome,"Ferritic steels possibly strengthened by oxide dispersion are candidates as
+structural materials for generation IV and fusion nuclear reactors. Their use
+is limited by incomplete knowledge of the iron-chromium phase diagram at low
+temperatures and of the phenomena inducing preferential segregation of one
+element at grain boundaries or at surfaces. In this context, this work
+contributes to the multi-scale study of the model iron-chromium alloy and their
+free surfaces by numerical simulations. This study begins with ab initio
+calculations of properties related to the mixture of atoms of iron and
+chromium. We highlight complex dependency of the magnetic moments of the
+chromium atoms on their local chemical environment. Surface properties are also
+proving sensitive to magnetism. This is the case of impurity segregation of
+chromium in iron and of their interactions near the surface. In a second step,
+we construct a simple energy model for high numerical efficiency. It is based
+on pair interactions on a rigid lattice to which are given local chemical
+environment and temperature dependencies. With this model, we reproduce the ab
+initio results at zero temperature and experimental results at high
+temperature. We also deduce the solubility limits at all intermediate
+temperatures with mean field approximations that we compare to Monte Carlo
+simulations. The last step of our work is to introduce free surfaces in our
+model. We then study the effect of ab initio calculated bulk and surface
+properties on surface segregation. Finally, we calculate segregation isotherms.
+We therefore propose an evolution model of surface composition of iron-chromium
+alloys as a function of bulk composition.",1303.2938v1
+2013-04-23,Quantitative study of the spin Hall magnetoresistance in ferromagnetic insulator/normal metal hybrids,"We experimentally investigate and quantitatively analyze the spin Hall
+magnetoresistance effect in ferromagnetic insulator/platinum and ferromagnetic
+insulator/nonferromagnetic metal/platinum hybrid structures. For the
+ferromagnetic insulator we use either yttrium iron garnet, nickel ferrite or
+magnetite and for the nonferromagnet copper or gold. The spin Hall
+magnetoresistance effect is theoretically ascribed to the combined action of
+spin Hall and inverse spin Hall effect in the platinum metal top layer. It
+therefore should characteristically depend upon the orientation of the
+magnetization in the adjacent ferromagnet, and prevail even if an additional,
+nonferromagnetic metal layer is inserted between Pt and the ferromagnet. Our
+experimental data corroborate these theoretical conjectures. Using the spin
+Hall magnetoresistance theory to analyze our data, we extract the spin Hall
+angle and the spin diffusion length in platinum. For a spin mixing conductance
+of $4\times10^{14}\;\mathrm{\Omega^{-1}m^{-2}}$ we obtain a spin Hall angle of
+$0.11\pm0.08$ and a spin diffusion length of $(1.5\pm0.5)\;\mathrm{nm}$ for Pt
+in our thin film samples.",1304.6151v1
+2013-06-11,Crossover from injection to tunneling conduction mode and associated magneto-resistance in a single $Fe_{3}O_{4}$(111)/$Alq_{3}$/Co spin-valve device,"We demonstrate interface energy level engineering, exploiting the
+modification in energy band structure across Verwey phase transition of
+$Fe_{3}O_{4}$ electrode, in a $Fe_{3}O_{4}$(111)/$Alq_{3}$/Co vertical
+spin-valve (SV) device. Experimental results on device characteristics I-V)
+study exhibit a transition in conduction mode from carrier injection to
+tunneling across Verwey transition temperature ($T_{V}$) of $Fe_{3}O_{4}$
+electrode. Both giant magneto-resistance (GMR) and tunneling MR (TMR) have been
+observed in a single SV device as a function of temperature, below and above
+$T_{V}$, respectively. Appearance of GMR, accompanied by injection limited
+natural Schottky-like I-V characteristics, provide evidences of spin injection
+at electrode/$Alq_{3}$ interface and transport through molecular orbitals in
+this SV device. Features of TMR exhibit significant differences from that of
+GMR. This is due to the dominant hyperfine-field interaction in the multi-step
+tunneling regime. We have achieved room-temperature SV operation in our device.
+A phenomenological model for device operation has been proposed to explain the
+transition in the conduction mode and associated MR features across $T_{V}$. We
+propose that the tuning of charge gap at Fermi level across Verwey transition
+due to charge ordering on the octahedral iron sites of $Fe_{3}O_{4}$ results in
+a corresponding tuning of conduction mode causing this unique cross over from
+GMR to TMR in this ferrite-based organic SV.",1306.2490v1
+2013-06-25,Nonmonotonic Relaxation as a Result of Spatial Heterogeneity in the Model of In-series Blocks Chain,"Recently the materials possessing structure of molecular and supramolecular
+matrix are more and more actively studied. They are relative to many polymeric
+materials of a technological origin, such as rubber, and living biological
+tissues. Processes of mechanical deformation of these continuous media have
+peculiarities connected, first, with accounting for internal friction and
+dissipation of energy, and secondly, with nonlinearity of their elastic and
+viscous properties, that is with violation of Hook and Newtons laws.
+Traditional approaches to mechanics of viscoelastic bodies sometimes are
+excessively difficult, and more evident and available representations are
+necessary. The invaluable role in studying of the operating processes
+mechanisms of elastic deformation and motility of biological materials is
+played by the mathematical modeling. New effect obtained by means of computer
+experiment of nonmonotonic relaxation of deformation in heterogeneous media is
+considered in the present work. Rheological properties of described media are
+governed by the differential equations of the first order on time (the
+evolution equations), as well as a huge variety of other physical processes.
+The physical phenomena in nonlinear systems with dissipation have a big
+community, including such it would seem far areas, as dynamics of magnetization
+in ferrite. Therefore the problem of studying new effects of viscous friction
+in the conditions of nonlinearity and heterogeneity, is very actual as in
+respect of fundamental research nonlinear and non-uniform environments, and in
+many areas of materials science, design of new materials, engineering of
+biological substitutes of living tissues and development of the micromagnetic
+devices using essentially new opportunities.",1306.5845v2
+2013-11-23,Universal Scaling Law to Predict the Efficiency of Magnetic Nanoparticles as MRI T2-Contrast Agents,"Magnetic particles are very efficient Magnetic Resonance Imaging (MRI)
+contrast agents. In the recent years, chemists have unleashed their imagination
+to design multi-functional nanoprobes for biomedical applications including MRI
+contrast enhancement. This study is focused on the direct relationship between
+the size and magnetization of the particles and their nuclear magnetic
+resonance relaxation properties, which condition their efficiency. Experimental
+relaxation results with maghemite particles exhibiting a wide range of sizes
+and magnetizations are compared to previously published data and to
+well-established relaxation theories with a good agreement. This allows
+deriving the experimental master curve of the transverse relaxivity versus
+particle size and to predict the MRI contrast efficiency of any type of
+magnetic nanoparticles. This prediction only requires the knowledge of the size
+of the particles impermeable to water protons and the saturation magnetization
+of the corresponding volume. To predict the T2 relaxation efficiency of
+magnetic single crystals, the crystal size and magnetization obtained through a
+single Langevin fit of a magnetization curve is the only information needed.
+For contrast agents made of several magnetic cores assembled into various
+geometries (dilute fractal aggregates, dense spherical clusters, core-shell
+micelles, hollow vesicles), one needs to know a third parameter, namely the
+intra-aggregate volume fraction occupied by the magnetic materials relatively
+to the whole (hydrodynamic) sphere. Finally a calculation of the maximum
+achievable relaxation effect and the size needed to reach this maximum is
+performed for different cases: maghemite single crystals and dense clusters,
+core-shell particles (oxide layer around a metallic core) and zinc manganese
+ferrite crystals.",1311.6022v1
+2014-01-16,Effect of Structural Transition on Magnetic Properties of Ca and Mn co-substituted BiFeO3 Ceramics,"Composition-driven structural transitions in Bi1-xCaxFe1-xMnxO3 ceramics
+prepared by the tartaric acid modified sol-gel technique have been studied to
+analyze its effect on the magnetic properties of bismuth ferrite (BiFeO3). It
+was observed that the co-substitution of Ca & Mn at Bi & Fe sites in BiFeO3
+(BFO) significantly suppress the impurity phases. The quantitative
+crystallographic phase analysis has been carried out by double phase Rietveld
+analysis of all the XRD patterns which indicates the existence of compositional
+driven crystal structure transformation from rhombohederal (R3c space group,
+lower crystal symmetry) to the orthorhombic (Pbnm space group, higher crystal
+symmetry) with the increase in substitution concentration due to excess
+chemical pressure (lattice strain). Magnetic measurements reveal that
+co-substituted BFO nanoparticles for x = 0.15 have enhanced remnant
+magnetization about 14 times that of pure one due to the suppression of cycloid
+spin structure which could be explained in terms of field induced spin
+reorientation and weak ferromagnetism. However, at the morphological phase
+boundary (x = 0.15), the remnant and maximum magnetization at 8 T reaches a
+maximum which indicates almost broken spin cycloid structure and further
+increase in substitution results in the reduction of both magnetizations due to
+the appearance of complete antiferromagnetic ordering in the orthorhombic
+structure because of the significant contribution from the crystallographic
+phase of Pbnm space group (as obtained from double phase Rietveld analysis).",1401.4059v1
+2014-04-11,Effect of Structural Transition on Magnetic and Dielectric Properties of La and Mn co-substituted BiFeO3 Ceramics,"Bi1-xLaxFe1-xMnxO3 (x = 0.000 - 0.300) ceramics prepared by the tartaric acid
+modified sol-gel technique have been studied to analyze the effect of
+composition driven structural transition on the magnetic properties of bismuth
+ferrite (BiFeO3). It was found that the co-substitution of La & Mn at Bi & Fe
+sites leads to suppression of impurity phases (Bi2Fe4O9 and Bi25FeO40) which
+generally appear in BiFeO3. The quantitative crystallographic phase analysis
+has been carried out by double phase Rietveld analysis of all the XRD patterns
+which indicates the existence of compositional driven crystal structure
+transformation from rhombohederal (space group R3c) to the orthorhombic (space
+group Pbnm) with the increase in substitution concentration. The 5%
+co-substituted sample exhibit high remnant magnetization i.e. about 15 times
+that of BiFeO3 which is due to the suppression of cycloid spin structure and
+enhanced canting angle of antiferromagnetically ordered spins caused by the
+crystal lattice distortion. However, further increase in substitution results
+in the reduction of remnant magnetization and coercivity due to the appearance
+of complete antiferromagnetic ordering in the orthorhombic structure because of
+the significant contribution from the crystallographic phase of Pbnm space
+group (as obtained from double phase Rietveld analysis). The frequency
+independent higher dielectric constant and lower dielectric loss were observed
+for 5% co-substitution. Hence, this particular composition may be interesting
+for device applications.",1404.3025v2
+2014-04-14,Magneto-photonic phenomena at terahertz frequencies,"Magneto-terahertz phenomena are the main focus of the thesis. This work
+started as supporting research for the science of an X-ray laser (SwissFEL).
+X-ray lasers have recently drawn great attention as an unprecedented tool for
+scientific research on the ultrafast scale..... To answer this fundamental
+question, we performed original numerical simulations using a coupled Landau-
+Lifshitz-Gilbert Maxwell model. ... Those requirements were the motivations for
+the experiments performed in the second part of the thesis. To shape the
+terahertz pulses, .... Regarding the field intensities, we followed two
+approaches. The first deals with field enhancement in nanoslits arrays. We
+designed a subwavelength structure characterized by simultaneous high field
+enhancement and high transmission at terahertz frequencies to suit nonlinear
+sources. The second approach depended on up-scaling the generation from
+laser-induced plasma by increasing the pump wavelengths. Numerical calculations
+have also brought to our attention the importance of linear magnetoterahertz
+effects. In particular, the simulations showed that the ultrafast dynamics
+could lead to significant rotation of the polarization plane of the triggering
+terahertz pulse. Motivated by this finding, we focused in the last part of the
+thesis on the linear effects. We performed three original studies coming out
+with first demonstrations of broadband non-reciprocal terahertz phase
+retarders, terahertz magnetic modulators, and the non-reciprocal terahertz
+isolators. In the first two experiments, we extended the unique properties of
+the magnetic liquids (Ferrofluids) to the terahertz regime. In the latter
+experiment, we used a permanent magnet (Ferrite) to experimentally show
+complete isolation (unidirectional transmission) of the terahertz waves.",1404.3764v1
+2014-07-11,Effects of dilute substitutional solutes on carbon in $α$-Fe: interactions and associated carbon diffusion from first-principles calculations,"By means of first-principles calculations coupled with the kinetic Monte
+Carlo simulations, we have systematically investigated the effects of dilute
+substitutional solutes on the behaviors of carbon in $\alpha$-Fe. Our results
+uncover that: ($i$) Without the Fe vacancy the interactions between most
+solutes and carbon are repulsive due to the strain relief, whereas Mn has a
+weak attractive interaction with its nearest-neighbor carbon due to the local
+ferromagnetic coupling effect. ($ii$) The presence of the Fe vacancy results in
+attractive interactions of all the solutes with carbon. In particular, the
+Mn-vacancy pair shows an exceptionally large binding energy of -0.81 eV with
+carbon. ($iii$) The alloying addition significantly impacts the atomic-scale
+concentration distributions and chemical potential of carbon in the Fe matrix.
+Among them, Mn and Cr increase the carbon chemical potential whereas Al and Si
+reduce it. ($iv$) Within the dilute scale of the alloying solution, the solute
+concentration and temperature dependent carbon diffusivities demonstrate that
+Mn has a little impact on the carbon diffusion whereas Cr (Al or Si) remarkably
+retards the carbon diffusion. Our results provide certain implication for
+better understanding the experimental observations related with the carbon
+solubility limit, carbon micro-segregation and carbide precipitations in the
+ferritic steels.",1407.2993v1
+2014-07-27,Josephson parametric phase-locked oscillator and its application to dispersive readout of superconducting qubits,"The parametric phase-locked oscillator (PPLO), also known as a parametron, is
+a resonant circuit in which one of the reactances is periodically modulated. It
+can detect, amplify, and store binary digital signals in the form of two
+distinct phases of self-oscillation. Indeed, digital computers using PPLOs
+based on a magnetic ferrite ring or a varactor diode as its fundamental logic
+element were successfully operated in 1950s and 1960s. More recently, basic bit
+operations have been demonstrated in an electromechanical resonator, and an
+Ising machine based on optical PPLOs has been proposed. Here, using a PPLO
+realized with Josephson-junction circuitry, we demonstrate the demodulation of
+a microwave signal digitally modulated by binary phase-shift keying. Moreover,
+we apply this demodulation capability to the dispersive readout of a
+superconducting qubit. This readout scheme enables a fast and latching-type
+readout, yet requires only a small number of readout photons in the resonator
+to which the qubit is coupled, thus featuring the combined advantages of
+several disparate schemes. We have achieved high-fidelity, single-shot, and
+non-destructive qubit readout with Rabi-oscillation contrast exceeding 90%,
+limited primarily by the qubit's energy relaxation.",1407.7195v1
+2014-09-24,Radiation-induced softening of Fe and Fe-based alloys during in-situ electron irradiation under mechanical testing,"Defects formed under irradiation in the bulk act as additional pinning
+centers resulting in the well-known effect of radiation-induced hardening. On
+the other hand, there is a poorly understood but well-established effect of
+instant and reversible softening of metals subjected to various types of
+irradiation. This radiation-induced softening (RIS) effect should be taken into
+account both in the theory of radiation effects and in the engineering approach
+for technological applications. In the present paper, the RIS is investigated
+experimentally in polycrystalline technically pure iron (0.048%C) and in
+commercial ferritic steel. The effect of the electron beam on plastic
+deformation of bcc Fe is compared with that in fcc Al (99.5%). Electron energy
+ranged from 0.5 to 0.8 MeV. Reversible drop of the yield stress and
+radiation-induced reduction of the elongation to fracture are measured as
+functions of the electron current and specimen thickness. Rate theory of RIS is
+proposed, which takes into account the radiation-induced excitation of moving
+discrete breathers (DBs), recently proven to exist in bcc Fe, and their
+interaction with dislocations enhancing unpinning from structural defects. The
+behavior of the DBs is studied using classical MD simulations providing input
+for the modified rate theory, which eventually demonstrates a reasonable
+agreement with experimental data. The relevance of results to the in-reactor
+behavior of pressure vessel steels is discussed.",1409.6799v1
+2015-07-27,X-ray microtomography of heavy microstructures: the case of Plasma-Sprayed Tungsten and Tungsten-Steel MMC,"In this paper synchrotron microtomography on Plasma Sprayed Tungsten (PS-W)
+is presented and discussed. PS-W is a challenging material for microtomography
+since it exhibits a random porous network at different length-scales (from
+nanometers to micrometers) and is hardly penetrable by X-rays. Furthermore,
+inner porosity causes strong internal scattering. The key challenges were,
+firstly, to optimize the beam parameters considering the inherent trade-off
+between photon energy (penetration depth) and spatial resolution and, secondly,
+to develop effective signal filtering algorithms. Despite the limited
+signal-to-noise ratio detected, large volumes of PS-W could be reconstructed
+with good image quality and micrometric resolution (voxel size = 1.4 {\mu}m).
+As an important result, we report excellent image quality and higher
+penetration depth by applying the same setup on a ferrous microstructure,
+namely a 10%W/Steel MMC used as interlayer between PS-W and a
+ferritic/martensitic steel substrate. The paper reports a detailed 3D
+morphological analysis of all inclusion types in PS-W and W/Steel, which led to
+disclosure of a complex connected porous network in both media. The analysis is
+presented in terms of multiphase volume fraction, ratio of percolation and 3D
+shape descriptors. 3D percolation patterns are analyzed in detail and
+sensitivity towards segmentation threshold for the noise-affected PS-W region
+is discussed. Remarkably, percolation of the porous phase was found throughout
+the entire coating thickness of PS-W. In W-Steel MMC percolation was found in
+the perpendicular plane and interpreted as onset of delamination caused by
+thermomechanical stress.",1507.07547v3
+2016-10-01,Effects of biaxial strain on the improper multiferroicity in h-LuFeO3 films,"Elastic strain is potentially an important approach in tuning the properties
+of the improperly multiferroic hexagonal ferrites, the details of which have
+however been elusive due to the experimental difficulties. Employing the method
+of restrained thermal expansion, we have studied the effect of isothermal
+biaxial strain in the basal plane of h-LuFeO3 (001) films. The results indicate
+that a compressive biaxial strain significantly enhances the ferrodistortion,
+and the effect is larger at higher temperatures. The compressive biaxial strain
+and the enhanced ferrodistortion together, cause an increase in the electric
+polarization and a reduction in the canting of the weak ferromagnetic moments
+in h-LuFeO3, according to our first principle calculations. These findings are
+important for understanding the strain effect as well as the coupling between
+the lattice and the improper multiferroicity in h-LuFeO3. The experimental
+elucidation of the strain effect in h-LuFeO3 films also suggests that the
+restrained thermal expansion can be a viable method to unravel the strain
+effect in many other epitaxial thin film materials.",1610.00073v1
+2017-03-24,Electronic structure and direct observation of ferrimagnetism in multiferroic hexagonal YbFeO3,"The magnetic interaction between rare-earth and Fe ions in hexagonal
+rare-earth ferrites (h-REFeO3), may amplify the weak ferromagnetic moment on
+Fe, making these materials more appealing as multiferroics. To elucidate the
+interaction strength between the rare-earth and Fe ions as well as the magnetic
+moment of the rare-earth ions, element specific magnetic characterization is
+needed. Using X-ray magnetic circular dichroism, we have studied the
+ferrimagnetism in h-YbFeO3 by measuring the magnetization of Fe and Yb
+separately. The results directly show anti-alignment of magnetization of Yb and
+Fe ions in h-YbFeO3 at low temperature, with an exchange field on Yb of about
+17 kOe. The magnetic moment of Yb is about 1.6 \muB at low-temperature,
+significantly reduced compared with the 4.5 \muB moment of a free Yb3+. In
+addition, the saturation magnetization of Fe in h-YbFeO3 has a sizable
+enhancement compared with that in h-LuFeO3. These findings directly demonstrate
+that ferrimagnetic order exists in h-YbFeO3; they also account for the
+enhancement of magnetization and the reduction of coercivity in h-YbFeO3
+compared with those in h-LuFeO3 at low temperature, suggesting an important
+role for the rare-earth ions in tuning the multiferroic properties of h-REFeO3.",1703.08482v2
+2017-08-17,"Multiferroic Core-Shell Nanofibers, Assembly in a Magnetic field and Studies on MagnetoElectric Interactions","Ferromagnetic-ferroelectric nanocomposites are of interest for realizing
+strong strain mediated coupling between electric and magnetic subsystems due to
+high surface area-to-volume ratio. This report is on the synthesis of nickel
+ferrite (NFO) -barium titanate (BTO) core-shell nano-fibers, magnetic field
+assisted assembly into superstructures, and studies on magneto-electric (ME)
+interactions. Electrospinning techniques were used to prepare coaxial fibers of
+0.5-1.5 micron in diameter. The core-shell structure of annealed fibers was
+confirmed by electron microscopy and scanning probe microscopy. The fibers were
+assembled into discs and films in a uniform magnetic field or a field gradient.
+Studies on ME coupling in the assembled films and discs were done by magnetic
+field H induced polarization, magneto-dielectric effects at low frequencies and
+at 16-24 GHz, and low frequency ME voltage coefficients (MEVC). We measured 2~
+2-7% change in remnant polarization and in the permittivity for H = 7 kOe, and
+a MEVC of 0.4 mV/cm Oe at 30 Hz. A model has been developed for low-frequency
+ME effects in an assembly of fibers and takes into account dipole-dipole
+interactions between the fibers and fiber discontinuity. Theoretical estimates
+for the low-frequency MEVC have been compared with the data. These results
+indicate strong ME coupling in superstructures of the core-shell fibers.",1708.05231v1
+2020-07-08,"Probing low temperature non-equilibrium magnetic state in Co$_{2.75}$Fe$_{0.25}$O$_{4+δ}$ spinel oxide using dc magnetization, ac susceptibility and neutron diffraction experiments","The low temperature lattice structure and magnetic properties of
+Co$_{2.75}$Fe$_{0.25}$O$_4$ ferrite have been investigated using experimental
+results from synchrotron x-ray diffraction (SXRD), dc magnetization, ac
+susceptibility, neutron diffraction and neutron depolarization techniques. The
+samples have been prepared by chemical co-precipitation of the Fe and Co
+nitrates solution in high alkaline medium and subsequent thermal annealing of
+the precipitates in the temperature range of 200- 900 $^\circ$C. Rietveld
+refinement of the SXRD patterns at room temperature indicated two-phased cubic
+spinel structure for the samples annealed at temperatures 200-600 $^\circ$C.
+The samples annealed at temperatures 700 $^\circ$C and 900 $^\circ$C (CF90)
+have been best fitted with single phased lattice structure. Refinement of the
+neutron diffraction patterns in the temperature range of 5-300 K confirmed
+antiferromagnetic (AFM) Co$_3$O$_4$ and ferrimagnetic (FIM)
+Co$_{2.75}$Fe$_{0.25}$O$_4$ phases for the sample annealed at 600 $^\circ$C and
+single FIM phase of Co$_{2.75}$Fe$_{0.25}$O$_4$ for the CF90 sample. Magnetic
+measurements have shown a non-equilibrium magnetic structure, consisting of the
+high temperature FIM phase and low temperature AFM phase. The magnetic phases
+are sensitive to magnetic fields, where high temperature phase is suppressed at
+higher magnetic fields by enhancing the low temperature AFM phase, irrespective
+of annealing temperature of the samples.",2007.03906v1
+2016-11-23,Magnetometer Based On Spin Wave Interferometer,"We describe magnetic field sensor based on spin wave interferometer. Its
+sensing element consists of a magnetic cross junction with four micro-antennas
+fabricated at the edges. Two of these antennas are used for spin wave
+excitation and two others antennas are used for the detection of the inductive
+voltage produced by the interfering spin waves. Two waves propagating in the
+orthogonal arms of the cross may accumulate significantly different phase
+shifts depending on the magnitude and the direction of the external magnetic
+field. This phenomenon is utilized for magnetic field sensing. The sensitivity
+has maximum at the destructive interference condition, where a small change of
+the external magnetic field results in a drastic increase of the inductive
+voltage as well as the change of the output phase. We report experimental data
+obtained on a micrometer scale Y3Fe2(FeO4)3 cross structure. The change of the
+inductive voltage near the destructive interference point exceeds 40 dB per 1
+Oe. At the same time, the phase of the output exhibit a {\pi}-phase shift
+within 1 Oe. The data are collected for three different orientations of the
+sensor in magnetic field at room temperature. Taking into account low thermal
+noise in ferrite structures, the maximum sensitivity of spin wave magnetometer
+may exceed atta Tesla. Other appealing advantages include compactness, fast
+data acquisition and wide temperature operating range. The physical limits of
+spin wave interferometers are also discussed.",1611.08015v1
+2017-04-08,Effect of Frustrated Exchange Interactions and Spin-half Impurity on the Electronic Structure of Strongly Correlated NiFe$_{2}$O$_{4}$,"Spin-polarized density functional calculations, magnetization, and neutron
+diffraction measurements are carried out to investigate the magnetic exchange
+interactions and strong correlation effects in Yb substituted inverse spinel
+nickel ferrite. In the pristine form, the compound is found to be a mixed
+insulator under the Zaanen-Sawtazsky-Allen classification scheme as it features
+both charge transfer and Mott insulator mechanism. Estimation of magnetic
+exchange couplings reveals that both octahedral-octahedral and
+octahedral-tetrahedral spin-spin interactions are antiferromagnetic which is
+typical of a spin-frustrated triangular lattice. However, the latter is
+dominant compared to the former leading to a forced parallel alignment of the
+spins at the octahedral site which is in agreement with the results of neutron
+diffraction measurements. The substituent Yb is found to be settled in +3
+charge state, as confirmed from the XPS measurements, to behave like a
+spin-half impurity carried by the localized $f_{z(x^2-y^2)}$ orbital. The
+impurity $f$ spin significantly weakens the antiferromagnetic coupling with the
+spins at the tetrahedral site, which explains the experimental observation of
+fall in Curie temperature with Yb substitution.",1704.02454v2
+2017-04-21,Strain-gradient-induced magnetic anisotropy in straight-stripe mixed-phase bismuth ferrites: An insight into flexomagnetic phenomenon,"Implementation of antiferromagnetic compounds as active elements in
+spintronics has been hindered by their insensitive nature against external
+perturbations which causes difficulties in switching among different
+antiferromagnetic spin configurations. Electrically-controllable strain
+gradient can become a key parameter to tune the antiferromagnetic states of
+multiferroic materials. We have discovered a correlation between an
+electrically-written straight-stripe mixed-phase boundary and an in-plane
+antiferromagnetic spin axis in highly-elongated La-5%-doped BiFeO$_{3}$ thin
+films by performing polarization-dependent photoemission electron microscopy in
+conjunction with cluster model calculations. Model Hamiltonian calculation for
+the single-ion anisotropy including the spin-orbit interaction has been
+performed to figure out the physical origin of the link between the strain
+gradient present in the mixed phase area and its antiferromagnetic spin axis.
+Our findings enable estimation of the strain-gradient-induced magnetic
+anisotropy energy per Fe ion at around 5$\times$10$^{-12}$ eV m, and provide a
+new pathway towards an electric-field-induced 90$^{\circ}$ rotation of
+antiferromagnetic spin axis at room temperature by flexomagnetism.",1704.06627v1
+2012-04-24,Formation mechanisms and relaxation of NMR spin-echo signals excited by two arbitrary duration radio-frequency pulses in magnets,"The work is devoted to the problem of multiple signals of nuclear spin echoes
+in magnets, excited by a series of radio-frequency (RF) arbitrary duration
+pulses exceeding the free induction decay time. The quantum-statistical
+approach based on the Liouville equation solution for the statistical operator
+of system is developed for the investigation of echo-processes. The obtained
+theoretical results for the number of echo signals, time moments of their
+formation and their intensities are in good agreement with experiments carried
+out on magnets (ferrites, ferrometals, half metals, manganites). The pointed
+approach is general and could be applied to EPR and NQR, which is interesting
+also for its application for remote detection of explosives and narcotics. The
+application of wide RF pulses and their sequences makes it possible to
+accumulate weak signals, enriches the echo-response spectrum with clearly
+separated intensive lines, i.e. essentially increases the sensitivity of
+apparatus and, correspondingly, the possibilities to explore the fine details
+of dynamical and relaxation processes taking place in nuclear spin-systems with
+sufficiently long relaxation times. The work contains also results of new
+experiments on study of relaxation processes in these systems.",1204.5344v2
+2014-05-27,Effect of Rhombohedral to Orthorhombic Transition on Magnetic and Dielectric Properties of La and Ti co-substituted BiFeO3,"Polycrystalline La and Ti co-substituted ceramics were synthesized by the
+tartaric acid modified sol-gel technique. It was observed that the
+co-substitution of La & Ti at Bi & Fe sites in BiFeO3 suppress the impurity
+phase formation which is a common problem in bismuth ferrite. The quantitative
+crystallographic phase analysis was performed with the help of FULLPROF program
+which suggests the existence of compositional driven crystal structure
+transition from rhombohederal (space group R3c) to the orthorhombic (space
+group Pbnm). The changes in the phonon frequencies as well as line widths of A1
+mode in Raman spectra reveal the lattice distortion which tends to modify the
+crystal structure. The structural transition breaks the spin cycloid structure
+in co-substituted BiFeO3 nanoparticles which leads to canting of the
+antiferromagnetic spin structure. Hence, the remnant magnetization increases up
+to 10 % of co-substitution and becomes 22 times that of BiFeO3. However, it
+decreases for higher co-substitution percentage due to significant contribution
+from the collinear antiferromagnetic ordering in the orthorhombic crystal
+symmetry. The co-substitution significantly enhanced the dielectric constant
+(maximum in x = 0.100) as well as frequency independent region for dielectric
+constant and dielectric loss.",1405.6878v1
+2015-12-18,A multiferroic on the brink: uncovering the nuances of strain-induced transitions in BiFeO$_3$,"Bismuth ferrite (BiFeO$_3$) is one of the very few known single-phase
+multiferroic materials. While the bulk compound is rhombohedral (R), the
+discovery of an epitaxial strain-induced structural transition into a so-called
+'super tetragonal-phase' (T-phase) in this material incited a flurry of
+research activity focused on gaining an understanding of this phase transition
+and its possible functionalities. This metastable phase of BiFeO$_3$ is also
+multiferroic, with giant ferroelectric polarization and coexisting
+antiferromagnetic order, but above all it is the strain relaxation-induced
+phase mixtures and their outstanding piezoelectric and magnetoelectric
+responses which continue to intrigue and motivate the physicist and materials
+scientist communities. Here, we review the research into the T-phase and
+mixed-phase BiFeO$_3$ system. We begin with a brief summary of the history of
+the T-phase and an analysis of the structure of the various phases reported in
+the literature. We then address important questions regarding the symmetry and
+octahedral rotation patterns and the (as yet underexplored) important role of
+chemistry in the formation of the metastable T-phase. We follow by describing
+the phase transitions in this material, and how these may hold promise for
+large magnetoelectric responses. Finally we point out some experimental
+challenges inherent to the study of such a system, and potential pathways for
+how they may be overcome. It is our intention with this work to highlight
+important issues that, in our opinion, should be carefully considered by the
+community in order to use this fascinating materials system for a new paradigm
+of functionality.",1512.05835v1
+2016-05-05,"Structural, optical and complex impedance spectroscopy study of multiferroic Bi2Fe4O9 ceramic","Multiferroic bismuth ferrite Bi_2Fe_4O_9 (BFO) ceramic was synthesized by
+conventional solid state reaction route. X-ray diffraction and Rietveld
+refinement show formation of single phase ceramic with orthorhombic crystal
+structure (space group Pbam). The morphological study depicted a well-defined
+grain of size $\simeq$2{\mu}m. The optical studies were carried out by using
+UV-Vis spectrophotometer which shows a band gap of 1.53 eV and a green emission
+spectrum at 537 is observed in the Photoluminescence study. The frequency
+dependent dielectric study at various temperature revealed that the dielectric
+constant decreases with increase in frequency. A noticeable peak shift towards
+higher frequency with increasing temperature is observed in the frequency
+dependent dielectric loss plot. The impedance spectroscopy shows a substantial
+shift in imaginary impedance (Z"") peaks toward the high frequency side
+described that the conduction in material favoring the long range motion of
+mobile charge carriers. The presence of non-Debye type multiple relaxations has
+been confirmed by complex modulus analysis. The frequency dependent ac
+conductivity at different temperatures indicates that the conduction process is
+thermally activated. The variation of dc conductivity exhibited a negative
+temperature coefficient of resistance behavior. The activation energy
+calculated from impedance, modulus and conductivity data confirmed that the
+oxygen vacancies play a vital role in the conduction mechanism.",1605.01574v1
+2017-06-14,Effects of the Hubbard U on density functional-based predictions of BiFeO$_3$ properties,"First principles studies of multiferroic materials, such as bismuth ferrite
+(BFO), require methods that extend beyond standard density functional theory
+(DFT). The DFT+U method is one such extension that is widely used in the study
+of BFO. We present a systematic study of the effects of the U parameter on the
+structural, ferroelectric and electronic properties of BFO. We find that the
+structural and ferroelectric properties change negligibly in the range of U
+typically considered for BFO (3-5 eV). In contrast, the electronic structure
+varies significantly with U. In particular, we see large changes to the
+character and curvature of the valence band maximum and conduction band
+minimum, in addition to the expected increase in band gap, as U increases. Most
+significantly, we find that the $t_{2g}$/$e_{g}$ ordering, expected from
+crystal field theory, is inverted for U values larger than 4 eV. We therefore
+recommend a U value of at most 4 eV to be applied to the Fe $d$ orbitals in
+BFO. More generally, this study emphasises the need for systematic
+investigations of the effects of the U parameter not merely on band gaps but on
+the electronic structure as a whole, especially for strongly correlated
+materials.",1706.04369v2
+2017-06-23,Fabrication of highly dense isotropic Nd-Fe-B bonded magnets via extrusion-based additive manufacturing,"Isotropic bonded magnets with a high loading fraction of 70 vol.% Nd-Fe-B are
+fabricated via an extrusion-based additive manufacturing, or 3D printing system
+that enables rapid production of large parts for the first time. The density of
+the printed magnet is 5.15 g/cm3. The room temperature magnetic properties are:
+intrinsic coercivity Hci = 8.9 kOe (708.2 kA/m), remanence Br = 5.8 kG (0.58
+Tesla), and energy product (BH)max = 7.3 MGOe (58.1 kJ/m3). The as-printed
+magnets are then coated with two types of polymers, both of which improve the
+thermal stability at 127 {\deg}C as revealed by flux aging loss measurements.
+Tensile tests performed at 25 {\deg}C and 100 {\deg}C show that the ultimate
+tensile stress (UTS) increases with increasing loading fraction of the magnet
+powder, and decreases with increasing temperature. AC magnetic susceptibility
+and resistivity measurements show that the 3D printed Nd-Fe-B bonded magnets
+exhibit extremely low eddy current loss and high resistivity. Finally, we show
+that through back electromotive force measurements that motors installed with
+3D printed Nd-Fe-B magnets exhibit similar performance as compared to those
+installed with sintered ferrites.",1706.07792v1
+2017-12-12,"Refutation of [Chyba and Hand, Phys. Rev. Applied 6, 014017 (2016)]: No Electric Power can be Generated from Earth's Rotation through its Own Magnetic Field","In a recent article [Phys. Rev. Applied 6, 014017 (2016)], Chyba and Hand
+propose a new scheme to generate electric power continuously at the expense of
+Earth's kinetic energy of rotation, by using an appropriately shaped
+cylindrical shell of a well chosen conducting ferrite, rigidly attached to the
+Earth. No experimental confirmation is reported for the new prediction. In the
+present Refutation, I first use today's standard electromagnetism and
+essentially the same model as Chyba and Hand to show in a very simple way that
+no device of the proposed type can produce continuous electric power, whatever
+its configuration or size, in agreement with widespread expectation. Next, I
+show that the prediction of non-zero continuous power by Chyba and Hand results
+from a confusion of frames of reference at a critical step of their derivation.
+When the confusion is clarified, the prediction becomes exactly zero and the
+article under discussion appears as pointless. At the end, I comment about the
+persistent invocation by Chyba and Hand of the misleading legacy notion that
+quasi-static magnetic fields have an intrinsic velocity, and other questionable
+concepts.",1712.04283v4
+2018-01-04,Effect of in-situ electric field assisted growth on anti-phase boundaries in epitaxial Fe3O4 thin films on MgO,"Anti-phase boundaries (APBs) normally form as a consequence of the initial
+growth conditions in all spinel ferrite thin films. The presence of APBs in
+epitaxial films of the inverse spinel Fe3O4 alters their electronic and
+magnetic properties due to strong antiferromagnetic (AF) interactions across
+these boundaries. The effect of using in-situ electric field assisted growth on
+the migration of APBs in hetero epitaxial Fe3O4(100)/MgO(100) thin films have
+been explored in the present work. The electric field assisted growth is found
+to reduce the AF interactions across APBs and as a consequence APBs free thin
+film like properties are obtained, which have been probed by electronic,
+magnetic and structural characterization. An increase in energy associated with
+the nucleation and/or early stage of the growth and, therefore, a corresponding
+increase in surface mobility of the ad-atoms play a critical role in
+controlling the density of APBs. This innovative technique can be employed to
+grow epitaxial spinel thin films with controlled AF interactions across APBs.",1801.01520v1
+2019-09-27,Microwave measurement beyond the quantum limit with a nonreciprocal amplifier,"The measurement of a quantum system is often performed by encoding its state
+in a single observable of a light field. The measurement efficiency of this
+observable can be reduced by loss or excess noise on the way to the detector.
+Even a \textit{quantum-limited} detector that simultaneously measures a second
+non-commuting observable would double the output noise, therefore limiting the
+efficiency to $50\%$. At microwave frequencies, an ideal measurement efficiency
+can be achieved by noiselessly amplifying the information-carrying quadrature
+of the light field, but this has remained an experimental challenge. Indeed,
+while state-of-the-art Josephson-junction based parametric amplifiers can
+perform an ideal single-quadrature measurement, they require lossy ferrite
+circulators in the signal path, drastically decreasing the overall efficiency.
+In this paper, we present a nonreciprocal parametric amplifier that combines
+single-quadrature measurement and directionality without the use of strong
+external magnetic fields. We extract a measurement efficiency of $62_{-9}^{+17}
+\%$ that exceeds the quantum limit and that is not limited by fundamental
+factors. The amplifier can be readily integrated with superconducting devices,
+creating a path for ideal measurements of quantum bits and mechanical
+oscillators.",1909.12964v2
+2019-10-04,"Partial time-reversal invariance violation in a flat, superconducting microwave cavity with the shape of a chaotic Africa billiard","We report on the experimental realization of a flat, superconducting
+microwave resonator, a microwave billiard, with partially violated
+time-reversal (T ) invariance, induced by inserting a ferrite into the cavity
+and magnetizing it with an external magnetic field perpendicular to the
+resonator plane. In order to prevent its expulsion caused by the
+Meissner-Ochsenfeld effect we used a cavity of which the top and bottom plate
+were made from niobium, a superconductor of type II, and cooled it down to
+liquid-helium temperature T LHe ' 4 K. The Cavity had the shape of a chaotic
+Afrivca billiard. Superconductivity rendered possible the accurate
+determination of complete sequences of the resonance frequencies and of the
+widths and strengths of the resonances, an indispensable prerequisite for the
+unambiguous detection of T invariance violation, especially when it is only
+partially violated. This allows for the first time the precise specification of
+the size of T invariance violation from the fluctuation properties of the
+resonance frequencies and from the strength distribution, which actually
+depends sensitively on it and thus provides a most suitable measure. For this
+purpose we derived an analytical expression for the latter which is valid for
+isolated resonances in the range from no T invariance violation to complete
+violation.",1910.04248v1
+2020-03-31,Comparative study of hydrogen embrittlement resistance between additively and conventionally manufactured austenitic stainless steels,"Hydrogen embrittlement in 304L (18wt.% Cr, 8-10wt.% Ni) austenitic stainless
+steel (ASS) fabricated by laser powder-bed-fusion (LPBF) was investigated by
+tensile testing after electrochemical hydrogen pre-charging and compared to
+conventionally available 304L ASSs with two different processing histories, (i)
+casting plus annealing (CA) and (ii) CA plus thermomechanical treatment (TMT).
+It was revealed that hydrogen-charging led to a significant reduction in
+ductility for the CA sample, but only a small effect of hydrogen was observed
+for the LPBF and CA-TMT samples. Hydrogen-assisted cracking behavior was found
+to be strongly linked to strain-induced martensitic transformation. In
+addition, the amount of alpha' martensite was much higher in the CA sample than
+in other samples, suggesting that severe hydrogen embrittlement can be
+correlated with the low mechanical stability of austenite. Detailed
+microstructural characterization showed that low austenite stability of the CA
+sample was mainly attributed to the retained content of delta ferrite and the
+chemical inhomogeneity inside the gamma matrix (gamma close to delta has ~2
+wt.% higher Cr but ~2 wt.% lower Ni), but TMT enhanced the chemical homogeneity
+and thus austenite stability. By contrast, the LPBF process led directly, i.e.
+without any thermomechanical treatment, to a fully austenitic structure with
+homogeneous elemental distribution in the ASS. These results confirmed that the
+presence of delta and the chemical inhomogeneity inside gamma matrix, which
+promoted the deformation-induced martensitic transformation and the associated
+H enrichment at the gamma-alpha' interface, was the primary reason for the
+severe H-assisted failure.",2004.00085v1
+2020-12-26,Structure and soft magnetic properties of single-domain Mg$_{1-x}$Ni$_x$Fe$_2$O$_4$ ($0 \le x \le 1.0$) nanocrystals,"The effects of Ni$^{2+}$ substitution on the structure (lattice parameters,
+cations distribution, average cations radii, cation-cation/anion bond lengths
+and angles) and the soft magnetic properties of Mg$_{1-x}$Ni$_x$Fe$_2$O$_4$ ($0
+\le x \le 1.0$) nanocrystals have been studied by x-ray diffraction with
+Rietveld refinement, transmittance electron microscopy, Mossbauer spectroscopy
+and magnetization measurements. The mostly inverse spinel structure was found
+in MgFe$_2$O$_4$ nanoparticles and the inversion factor is further increased by
+Ni-substitution up to a complete inversion in NiFe$_2$O$_4$. The synthesized
+ferrites with a small particle size (20 - 30 nm) exhibit soft magnetic
+properties of a single-domain behavior with critical domain size about 30 - 40
+nm. An observed monotonic increase in magnetization and drastic decrease in
+coercivity at 5 K by Ni-substitution result in a lowest anisotropy constant Ku
+(2.8 kJ/m3) for x = 0.5. We discuss the evolution of magnetic properties by
+Ni-substitution in a correlation with a subsequent cations-redistribution
+between sites of the two sublattices and corresponding structural changes in
+the inter-ionic distances.",2012.13819v1
+2017-11-09,Switchable Ferroelectric Photovoltaic Effects in Epitaxial Thin Films of h-RFeO3 having Narrow Optical Band Gaps,"Ferroelectric photovoltaics (FPVs) have drawn much attention owing to their
+high stability, environmental safety, anomalously high photovoltages, coupled
+with reversibly switchable photovoltaic responses. However, FPVs suffer from
+extremely low photocurrents, which is primarily due to their wide band gaps.
+Here, we present a new class of FPVs by demonstrating switchable ferroelectric
+photovoltaic effects using hexagonal ferrite (h-RFeO3) thin films having narrow
+band gaps of ~1.2 eV, where R denotes rare-earth ions. FPVs with narrow band
+gaps suggests their potential applicability as photovoltaic and optoelectronic
+devices. The h-RFeO3 films further exhibit reasonably large ferroelectric
+polarizations, which possibly reduces a rapid recombination rate of the
+photo-generated electron-hole pairs. The power conversion efficiency (PCE) of
+h-RFeO3 thin-film devices is sensitive on the magnitude of polarization. In the
+case of h-TmFeO3 (h-TFO) thin film, the measured PCE is twice as large as that
+of the BiFeO3 thin film, a prototypic FPV. We have further shown that the
+switchable photovoltaic effect dominates over the unswitchable internal field
+effect arising from the net built-in potential. This work thus demonstrates a
+new class of FPVs towards high-efficiency solar cell and optoelectronic
+applications.",1711.03250v1
+2018-03-12,Understanding the mechanical properties of reduced activation steels,"Reduced activation ferritic/martensitic (RAFM) steels are structural
+materials with potential application in Generation-IV fission and fusion
+reactors. We use density-functional theory to scrutinize the micro-mechanical
+properties of the main alloy phases of three RAFM steels based on the
+body-centered cubic FeCrWVMn solid solution. We assess the lattice parameters
+and elastic properties of ferromagnetic $\alpha$-Fe and Fe$_{91}$Cr$_{9}$,
+which are the main building blocks of the RAFM steels, and present a detailed
+analysis of the calculated alloying effects of V, Cr, Mn, and W on the
+mechanical properties of Fe$_{91}$Cr$_{9}$. The composition dependence of the
+elastic parameters is decomposed into electronic and volumetric contributions
+and studied for alloying levels that cover the typical intervals in RAFM
+steels. A linear superposition of the individual solute effects on the
+properties of Fe$_{91}$Cr$_{9}$ is shown to provide an excellent approximation
+for the \emph{ab initio} values obtained for the RAFM steels. The intrinsic
+ductility is evaluated through Rice's phenomenological theory using the surface
+and unstable stacking fault energies, and the predictions are contrasted with
+those obtained by empirical criteria. Alloying with V or W is found to enhance
+the ductility, whereas additional Cr or Mn turns the RAFM base alloys more
+brittle.",1803.04178v1
+2018-03-24,Microstructural constitutive model for polycrystal viscoplasticity in cold and warm regimes based on continuum dislocation dynamics,"Viscoplastic flow of polycrystalline metallic materials is the result of
+motion and interaction of dislocations, line defects of the crystalline
+structure. In the microstructural (physics-based) constitutive model presented
+in this paper, the main underlying microstructural processes influencing
+viscoplastic deformation and mechanical properties of metals in cold and warm
+regimes are statistically described by the introduced sets of postulates/axioms
+for continuum dislocation dynamics (CDD). Three microstructural (internal)
+state variables (MSVs) are used for statistical quantifications of different
+types/species of dislocations by the notion of dislocation density. Considering
+the mobility property of dislocations, they are categorized to mobile and
+(relatively) immobile dislocations. Mobile dislocations carry the plastic
+strain (rate), while immobile dislocations contribute to plastic hardening.
+Moreover, with respect to their arrangement, dislocations are classified to
+cell and wall dislocations. Cell dislocations are those that exist inside
+cells/subgrains, and wall dislocations are packed in (and consequently formed)
+the subgrain walls/boundaries. Therefore, the MSVs incorporated in this model
+are cell mobile, cell immobile and wall immobile dislocation densities. The
+evolution of these internal variables is calculated by means of adequate
+equations that characterize the dislocation processes dominating material
+behavior during cold and warm monotonic viscoplastic deformation. The
+constitutive equations are then numerically integrated; and the constitutive
+parameters are determined/fitted for a widely used ferritic-pearlitic steel
+(20MnCr5).",1803.09174v3
+2019-01-22,Ferromagnetic-like behavior of Bi0.9La0.1FeO3-KBr nanocomposites,"We studied magnetostatic response of the Bi0.9La0.1FeO3-KBr composites
+(BLFO-KBr) consisting of nanosized (about 100 nm) ferrite Bi0.9La0.1FeO3 (BLFO)
+conjugated with fine grinded ionic conducting KBr. When the fraction of KBr is
+rather small (less than 15 wt percent) the magnetic response of the composite
+is very weak and similar to that observed for the BLFO (pure KBr matrix without
+Bi1-xLaxFeO3 has no magnetic response as anticipated). However, when the
+fraction of KBr increases above 15percent, the magnetic response of the
+composite changes substantially and the field dependence of magnetization
+reveals ferromagnetic-like hysteresis loop with a remanent magnetization about
+0.14 emu/g and coercive field about 1.8 Tesla (at room temperature). Nothing
+similar to the ferromagnetic-like hysteresis loop can be observed in BLFO
+ceramics, which magnetization quasi linearly increases with magnetic field.
+Different physical mechanisms were considered to explain the unusual
+experimental results for BLFO-KBr nanocomposites, but only those among them,
+which are highly sensitive to the interaction of antiferromagnetic
+Bi0.9La0.1FeO3 with ionic conductor KBr, can be relevant. An appropriate
+mechanism turned out to be ferro-magneto-ionic coupling.",1901.08913v1
+2019-04-05,"Stoichiometry, Phase, and Texture Evolution in PLD-Grown Hexagonal Barium Ferrite Films as a Function of Laser Process Parameters","Barium hexaferrite (BaFe12O19 or BaM) films were grown on c-plane sapphire
+(0001) substrates by pulsed laser deposition (PLD) to evaluate the effects of
+the laser fluence on their composition, structure, and magnetic properties.
+Continuum's Surelite pulsed 266nm Nd:YAG laser was employed, and the laser
+fluence varied systemically between 1 and 5.7 [J/cm2]. Deviations from the
+stoichiometric transfer between the BaM targets and deposited thin films
+occurred as the laser fluence changed. The Fe to Ba ratio in the films
+increased with the laser fluence. The films deposited at the laser fluences
+below 4 J/cm2 showed undesirable 3-dimensional islands on the surface.
+Moreover, insufficient laser energy resulted in the deposition of some
+secondary phases, for example, barium monoferrite (BaFe2O4) and Magnetite
+(Fe3O4). On the other hand, laser fluences above 5 J/cm2 promoted resputtering
+and degraded the film quality, structure, and magnetic properties. BaM films
+deposited at 4.8 J/cm2 - the optimal laser fluence - showed excellent c-axis
+orientation perpendicular to the film plane with the anisotropy field of 16 kOe
+and saturation magnetization of 4.39 kOe. These results clearly demonstrate a
+strong influence of the laser parameters on the PLD-grown hexaferrite films and
+pave the path for the high-yield production using PLD systems.",1904.03157v2
+2019-08-12,Rollable Magnetoelectric Energy Harvester as Wireless IoT Sensor,"Perhaps the most abundant form of waste energy in our surrounding is the
+parasitic magnetic noise arising from electrical power transmission system. In
+this work, a flexible and rollable magneto-mechano-electric nanogenerator
+(MMENG) based wireless IoT sensor has been demonstrated in order to capture and
+utilize the magnetic noise. Free standing magnetoelectric (ME) composites are
+fabricated by combining magnetostrictive nickel ferrite nanoparticles and
+piezoelectric polyvinylidene-co-trifluoroethylene polymer. The magnetoelectric
+0-3 type nanocomposites possess maximum ME co-efficient of 11.43 mV/cm-Oe.
+Even, without magnetic bias field 99 % of the maximum ME co-efficient value is
+observed due to self-bias effect. As a result, the MMENG generates sufficient
+peak-to-peak open circuit voltage, output power density and successfully
+operates commercial capacitor under the weak and low frequency stray magnetic
+field arising from the power cable of home appliances such as, electric kettle.
+Finally, the harvested electrical signal has been wirelessly transmitted to a
+smart phone in order to demonstrate the possibility of position monitoring
+system construction. This cost effective and easy to integrate approach with
+tailored size and shape of device configuration is expected to be explored in
+next-generation self-powered IoT sensors including implantable biomedical
+devices and human health monitoring sensory systems.",1908.04282v1
+2019-11-03,Ferromagnetic dynamics detected via one- and two-magnon NV relaxometry,"The NV center in diamond has proven to be a powerful tool for locally
+characterizing the magnetic response of microwave excited ferromagnets. To
+date, this has been limited by the requirement that the FMR excitation
+frequency be less than the NV spin resonance frequency. Here we report NV
+relaxometry based on a two-magnon Raman-like process, enabling detection of FMR
+at frequencies higher than the NV frequency. For high microwave drive powers,
+we observe an unexpected field-shift of the NV response relative to a
+simultaneous microwave absorption signal from a low damping ferrite film. We
+show that the field-shifted NV response is due to a second order Suhl
+instability. The instability creates a large population of non-equilibrium
+magnons which relax the NV spin, even when the uniform mode FMR frequency
+exceeds that of the NV spin resonance frequency, hence ruling out the
+possibility that the NV is relaxed by a single NV-resonant magnon. We argue
+that at high frequencies the NV response is due to a two-magnon relaxation
+process in which the difference frequency of two magnons matches the NV
+frequency, and at low frequencies we evaluate the lineshape of the one-magnon
+NV relaxometry response using spinwave instability theory.",1911.00829v1
+2019-12-09,Field Dependence of Magnetic Disorder in Nanoparticles,"The performance characteristics of magnetic nanoparticles towards
+application, e.g. in medicine, imaging, or as sensors, is directly determined
+by their magnetization relaxation and total magnetic moment. In the commonly
+assumed picture, nanoparticles have a constant overall magnetic moment
+originating from the magnetization of the single-domain particle core
+surrounded by a surface region hosting spin disorder. In contrast, this work
+demonstrates the significant increase of the magnetic moment of ferrite
+nanoparticles with applied magnetic field. At low magnetic field, the
+homogeneously magnetized particle core initially coincides in size with the
+structurally coherent grain of 12.8(2) nm diameter, indicating a strong
+coupling between magnetic and structural disorder. Applied magnetic fields
+gradually polarize the uncorrelated, disordered surface spins, resulting in a
+magnetic volume more than 20\% larger than the structurally coherent core. The
+intraparticle magnetic disorder energy increases sharply towards the
+defect-rich surface as established by the field-dependence of the magnetization
+distribution. In consequence, these findings illustrate how the nanoparticle
+magnetization overcomes structural surface disorder. This new concept of
+intraparticle magnetization is deployable to other magnetic nanoparticle
+systems, where the in-depth knowledge of spin disorder and associated magnetic
+anisotropies will be decisive for a rational nanomaterials design.",1912.04081v2
+2019-12-16,Universal spin-resolved thermal radiation laws for nonreciprocal bianisotropic media,"A chiral absorber of light can emit spin-polarized (circularly polarized)
+thermal radiation based on Kirchhoff's law which equates spin-resolved
+emissivity with spin-resolved absorptivity for reciprocal media at thermal
+equilibrium. No such law is known for nonreciprocal media. In this work, we
+discover three spin-resolved Kirchhoff's laws of thermal radiation applicable
+for both reciprocal and nonreciprocal planar media. In particular, these laws
+are applicable to multi-layered or composite slabs of generic bianisotropic
+material classes which include (uniaxial or biaxial) birefringent crystals,
+(gyrotropic) Weyl semimetals, magnetized semiconductors, plasmas, ferromagnets
+and ferrites, (magnetoelectric) topological insulators, metamaterials and
+multiferroic media. We also propose an experiment to verify these laws using a
+single system of doped Indium Antimonide (InSb) thin film in an external
+magnetic field. Furthermore, we reveal a surprising result that the planar
+slabs of all these material classes can emit partially circularly polarized
+thermal light without requiring any surface patterning, and identify planar
+configurations which can experience nontrivial thermal optomechanical forces
+and torques upon thermal emission into the external environment at lower
+temperature (nonequilibrium). Our work also provides a new fundamental insight
+of detailed balance of angular momentum (in addition to energy) of equilibrium
+thermal radiation, and paves the way for practical functionalities based on
+thermal radiation using nonreciprocal bianisotropic materials.",1912.07177v2
+2020-05-04,The Newspaper Navigator Dataset: Extracting And Analyzing Visual Content from 16 Million Historic Newspaper Pages in Chronicling America,"Chronicling America is a product of the National Digital Newspaper Program, a
+partnership between the Library of Congress and the National Endowment for the
+Humanities to digitize historic newspapers. Over 16 million pages of historic
+American newspapers have been digitized for Chronicling America to date,
+complete with high-resolution images and machine-readable METS/ALTO OCR. Of
+considerable interest to Chronicling America users is a semantified corpus,
+complete with extracted visual content and headlines. To accomplish this, we
+introduce a visual content recognition model trained on bounding box
+annotations of photographs, illustrations, maps, comics, and editorial cartoons
+collected as part of the Library of Congress's Beyond Words crowdsourcing
+initiative and augmented with additional annotations including those of
+headlines and advertisements. We describe our pipeline that utilizes this deep
+learning model to extract 7 classes of visual content: headlines, photographs,
+illustrations, maps, comics, editorial cartoons, and advertisements, complete
+with textual content such as captions derived from the METS/ALTO OCR, as well
+as image embeddings for fast image similarity querying. We report the results
+of running the pipeline on 16.3 million pages from the Chronicling America
+corpus and describe the resulting Newspaper Navigator dataset, the largest
+dataset of extracted visual content from historic newspapers ever produced. The
+Newspaper Navigator dataset, finetuned visual content recognition model, and
+all source code are placed in the public domain for unrestricted re-use.",2005.01583v1
+2020-06-01,Enhancement in Thermally Generated Spin Voltage at Pd/NiFe$_2$O$_4$ Interfaces by the Growth on Lattice-Matched Substrates,"Efficient spin injection from epitaxial ferrimagnetic NiFe$_2$O$_4$ thin
+films into a Pd layer is demonstrated via spin Seebeck effect measurements in
+the longitudinal geometry. The NiFe$_2$O$_4$ films (60 nm to 1 $\mu$m) are
+grown by pulsed laser deposition on isostructural spinel MgAl$_2$O$_4$,
+MgGa$_2$O$_4$, and CoGa$_2$O$_4$ substrates with lattice mismatch varying
+between 3.2% and 0.2%. For the thinner films ($\leq$ 330 nm), an increase in
+the spin Seebeck voltage is observed with decreasing lattice mismatch, which
+correlates well with a decrease in the Gilbert damping parameter as determined
+from ferromagnetic resonance measurements. High resolution transmission
+electron microscopy studies indicate substantial decrease of antiphase boundary
+and interface defects that cause strain-relaxation, i.e., misfit dislocations,
+in the films with decreasing lattice mismatch. This highlights the importance
+of reducing structural defects in spinel ferrites for efficient spin injection.
+It is further shown that angle-dependent spin Seebeck effect measurements
+provide a qualitative method to probe for in-plane magnetic anisotropies
+present in the films.",2006.00777v1
+2020-08-09,Efficient and Low-Backaction Quantum Measurement Using a Chip-Scale Detector,"Superconducting qubits are a leading platform for scalable quantum computing
+and quantum error correction. One feature of this platform is the ability to
+perform projective measurements orders of magnitude more quickly than qubit
+decoherence times. Such measurements are enabled by the use of quantum-limited
+parametric amplifiers in conjunction with ferrite circulators - magnetic
+devices which provide isolation from noise and decoherence due to amplifier
+backaction. Because these non-reciprocal elements have limited performance and
+are not easily integrated on-chip, it has been a longstanding goal to replace
+them with a scalable alternative. Here, we demonstrate a solution to this
+problem by using a superconducting switch to control the coupling between a
+qubit and amplifier. Doing so, we measure a transmon qubit using a single,
+chip-scale device to provide both parametric amplification and isolation from
+the bulk of amplifier backaction. This measurement is also fast, high fidelity,
+and has 70% efficiency, comparable to the best that has been reported in any
+superconducting qubit measurement. As such, this work constitutes a
+high-quality platform for the scalable measurement of superconducting qubits.",2008.03805v2
+2020-08-22,High-Performance Thermoelectric Oxides Based on Spinel Structure,"High-performance thermoelectric oxides could offer a great energy solution
+for integrated and embedded applications in sensing and electronics industries.
+Oxides, however, often suffer from low Seebeck coefficient when compared with
+other classes of thermoelectric materials. In search of high-performance
+thermoelectric oxides, we present a comprehensive density functional
+investigation, based on GGA$+U$ formalism, surveying the 3d and 4d
+transition-metal-containing ferrites of the spinel structure. Consequently, we
+predict MnFe$_2$O$_4$ and RhFe$_2$O$_4$ have Seebeck coefficients of $\sim \pm
+600$ $\mu$V K$^{-1}$ at near room temperature, achieved by light hole and
+electron doping. Furthermore, CrFe$_2$O$_4$ and MoFe$_2$O$_4$ have even higher
+ambient Seebeck coefficients at $\sim \pm 700$ $\mu$V K$^{-1}$. In the latter
+compounds, the Seebeck coefficient is approximately a flat function of
+temperature up to $\sim 700$ K, offering a tremendous operational convenience.
+Additionally, MoFe$_2$O$_4$ doped with $10^{19}$ holes/cm$^3$ has a calculated
+thermoelectric power factor of $689.81$ $\mu$W K$^{-2}$ m$^{-1}$ at $300$ K,
+and $455.67$ $\mu$W K$^{-2}$ m$^{-1}$ at $600$ K. The thermoelectric properties
+predicted here can bring these thermoelectric oxides to applications at lower
+temperatures traditionally fulfilled by more toxic and otherwise burdensome
+materials.",2008.09759v1
+2020-09-28,How T-invariance violation leads to an enhanced backscattering with increasing openness of a wave-chaotic system,"We report on the experimental investigation of the dependence of the elastic
+enhancement, i.e., enhancement of scattering in backward direction over
+scattering in other directions of a wave-chaotic system with partially violated
+time-reversal (T ) invariance on its openness. The elastic enhancement factor
+is a characteristic of quantum chaotic scattering which is of particular
+importance in experiments, like compound-nuclear reactions, where only cross
+sections, i.e., the moduli of the associated scattering matrix elements are
+accessible. In the experiment a quantum billiard with the shape of a quarter
+bow-tie, which generates a chaotic dynamics, is emulated by a flat microwave
+cavity. Partial T-invariance violation of varying strength 0 < xi < 1 is
+induced by two magnetized ferrites. The openness is controlled by increasing
+the number M of open channels, 2 < M < 9, while keeping the internal absorption
+unchanged. We investigate the elastic enhancement as function of xi and find
+that for a fixed M it decreases with increasing time-reversal invariance
+violation, whereas it increases with increasing openness beyond a certain value
+of xi > 0.2. The latter result is surprising because it is opposite to that
+observed in systems with preserved T invariance (xi = 0). We come to the
+conclusion that the effect of T -invariance violation on the elastic
+enhancement then dominates over the openness, which is crucial for experiments
+which rely on enhanced backscattering, since, generally, a decrease of the
+openness is unfeasible. Motivated by these experimental results we,
+furthermore, performed theoretical investigations based on random matrix theory
+which confirm our findings.",2009.13519v1
+2020-11-13,Magnetoelectric coupling and decoupling in multiferroic hexagonal YbFeO3 thin films,"The coupling between ferroelectric and magnetic orders in multiferroic
+materials and the nature of magnetoelectric (ME) effects are enduring
+experimental challenges. In this work, we have studied the response of
+magnetization to ferroelectric switching in thin-film hexagonal YbFeO3, a
+prototypical improper multiferroic. The bulk ME decoupling and potential
+domain-wall ME coupling were revealed using x-ray magnetic circular dichroism
+(XMCD) measurements with in-situ ferroelectric polarization switching. Our
+Landau theory analysis suggests that the bulk ME-coupled ferroelectric
+switching path has a higher energy barrier than that of the ME-decoupled path;
+this extra barrier energy is also too high to be reduced by the magneto-static
+energy in the process of breaking single magnetic domains into multi-domains.
+In addition, the reduction of magnetization around the ferroelectric domain
+walls predicted by the Landau theory may induce the domain-wall ME coupling in
+which the magnetization is correlated with the density of ferroelectric domain
+walls. These results provide important experimental evidence and theoretical
+insights into the rich possibilities of ME couplings in hexagonal ferrites,
+such as manipulating the magnetic states by an electric field.",2011.07154v1
+2021-03-20,Towards Superior High Temperature Properties in Low Density AlCrFeNiTi Compositionally Complex Alloys,"Three novel precipitation strengthened bcc alloys which exhibit a smooth
+microstructural gradient with composition have been fabricated in bulk form by
+induction casting. All three alloys are comprised of a mixture of disordered
+A2-(Fe, Cr) and L2$_1$-ordered (Ni, Fe)$_{2}$AlTi type phases both as-cast and
+after long-term annealing at 900 $^{\circ}$C. The ratio of disordered to
+ordered phase, primary dendrite fraction, and overall microstructural
+coarseness all decrease as Cr is replaced by Al and Ti. Differences in phase
+composition are quantified through domain averaged principal component analysis
+of energy dispersive spectroscopy data obtained during scanning transmission
+electron microscopy. Bulk tensile testing reveals retained strengths of nearly
+250 MPa up to 900 $^{\circ}$C for the alloys which contain a nanoscale
+maze-like arrangement of ordered and disordered phases. One alloy, containing a
+duplex microstructure with ductile dendritic regions and highly creep resistant
+interdendritic regions, shows a promising balance between high temperature
+ductility and strength. For this alloy, tension creep testing was carried out
+at 700, 750, and 800 $^{\circ}$C for a broad range of loading conditions and
+revealed upper bound creep rates which surpass similar ferritic superalloys and
+rival those of several conventionally employed high temperature structural
+alloys, including Inconel 617 and 718, at much lower density and raw material
+cost.",2103.11173v1
+2021-04-15,Morphotropic Phase Boundary in Sm-Substituted BiFeO3 Ceramics: Local vs Microscopic Approaches,"Samarium substituted bismuth ferrite (BiFeO3) ceramics prepared by sol-gel
+synthesis method were studied using both local scale and microscopic
+measurement techniques in order to clarify an evolution of the crystal
+structure of the compounds across the morphotropic phase boundary region. X-ray
+diffraction analysis, transmission and scanning electron microscopies, XPS,
+EDS/EDX experiments and piezoresponse force microscopy were used to study the
+structural transitions from the polar active rhombohedral phase to the
+anti-polar orthorhombic phase and then to the non-polar orthorhombic phase,
+observed in the Bi1-xSmxFeO3 compounds within the concentration range of 0.08 <
+x < 0.2. The results obtained by microscopic techniques testify that the
+compounds in the range of 0.12 < x < 0.15 are characterized by two phase
+structural state formed by a coexistence of the rhombohedral and the anti-polar
+orthorhombic phases; two phase structural state observed in the compounds with
+0.15 < x < 0.18 is associated with a coexistence of the anti-polar orthorhombic
+and the non-polar orthorhombic phases. Local scale measurements have revealed a
+notable difference in the concentration range ascribed to the morphotropic
+phase boundary estimated by microscopic measurements, the obtained results
+testify a wider concentration range ascribed to a coexistence of different
+structural phases, the background of the mentioned difference is discussed.",2104.07401v1
+2021-04-18,Impact of particle size on the magnetic properties of highly crystalline Yb3+ substituted Ni-Zn nanoferrites,"Yb-substituted Ni-Zn ferrites have been synthesized using sol-gel auto
+combustion method. The structural characterization of the compositions has been
+performed by X-ray diffraction analysis, field emission scanning electron
+microscopy (FESEM), quantum design physical properties measurement system
+(PPMS). That ensured the formation of single phase cubic spinel structure.
+Crystallite and average grain size are calculated and found to decrease with
+increasing Yb3+ contents. Saturation magnetization and Bohr magnetic moment
+decrease while the coercivity increases with the increase in Yb3+ contents
+successfully explained by the Neels collinear two sub-lattice model and
+critical size effect, respectively. Critical particle size has been estimated
+at 6.4 nm, the transition point between single domain regime (below the
+critical size) and multi-domain regime (beyond the critical size). Curie
+temperature reduces due to the weakening of A-O-B super exchange interaction
+and redistribution of cations, confirmed by the M-T graph. The compositions
+retain ferromagnetic ordered structured below Curie temperature and above Curie
+temperature, it becomes paramagnetic, making them plausible candidates for high
+temperature magnetic device applications. The relative quality factor peak is
+obtained at a very high frequency, indicating the compositions could also be
+applicable for high frequency magnetic device applications.",2104.08694v1
+2021-05-20,Evolution of topological defects at two sequential phase transitions of Nd2SrFe2O7,"How topological defects, unavoidable at symmetry-breaking phase transitions
+in a wide range of systems, evolve through consecutive phase transitions with
+different broken symmetries remains unexplored. Nd2SrFe2O7, a bilayer ferrite,
+exhibits two intriguing structural phase transitions and dense networks of the
+so-called type-II Z8 structural vortices at room temperature, so it is an ideal
+system to explore the topological defect evolution. From our extensive
+experimental investigation, we demonstrate that the cooling rate at the
+second-order transition (1290oC) plays a decisive role in determining the
+vortex density at room temperature, following the universal Kibble-Zurek
+mechanism. In addition, we discovered a transformation between
+topologically-distinct vortices (Z8 to Z4 vortices) at the first-order
+transition (550oC), which conserves the number of vortex cores. Remarkably, the
+Z4 vortices consist of two phases with an identical symmetry but two distinct
+magnitudes of an order parameter. Furthermore, when lattice distortion is
+enhanced by chemical doping, a new type of topological defects emerges: loop
+domain walls with orthorhombic distortions in the tetragonal background,
+resulting in unique pseudo-orthorhombic twins. Our findings open a new avenue
+to explore the evolution of topological defects through multiple phase
+transitions.",2105.09669v1
+2021-07-19,Deformation Behaviour of Ion-Irradiated FeCr: A Nanoindentation Study,"Understanding the mechanisms of plasticity in structural steels is essential
+for the operation of next-generation fusion reactors. Elemental composition,
+particularly the amount of Cr present, and irradiation can have separate and
+synergistic effects on the mechanical properties of ferritic/martensitic
+steels. The study of ion-irradiated FeCr alloys is useful for gaining a
+mechanistic understanding of irradiation damage in steels. Previous studies of
+ion-irradiated FeCr did not clearly distinguish between the nucleation of
+dislocations to initiate plasticity, and their propagation through the material
+as plasticity progresses.
+  In this study, Fe3Cr, Fe5Cr, and Fe10Cr were irradiated with 20 MeV Fe$^{3+}$
+ions at room temperature to nominal doses of 0.01 dpa and 0.1 dpa.
+Nanoindentation was carried out with Berkovich and spherical indenter tips to
+study the nucleation of dislocations and their subsequent propagation. The
+presence of irradiation-induced defects reduced the theoretical shear stress
+and barrier for dislocation nucleation. The presence of Cr further enhanced
+this effect due to increased retention of irradiation defects. However, this
+combined effect is still small compared to dislocation nucleation from
+pre-existing sources such as Frank-Read sources and grain boundaries. The yield
+strength, an indicator of dislocation mobility, of FeCr increased with
+irradiation damage and Cr. The increased retention of irradiation defects due
+to the presence of Cr also further increased the yield strength. Reduced work
+hardening capacity was also observed following irradiation. The synergistic
+effects of Cr and irradiation damage in FeCr appear to be more important for
+the propagation of dislocations, rather than their nucleation.",2107.09040v1
+2021-09-14,Design of a HOM-Damped 166.6 MHz Compact Quarter-Wave beta=1 Superconducting Cavity for High Energy Photon Source,"Superconducting cavities with low RF frequencies and heavy damping of higher
+order modes (HOM) are desired for the main accelerator of High Energy Photon
+Source (HEPS), a 6 GeV synchrotron light source promising ultralow emittance
+currently under construction in Beijing. A compact 166.6 MHz superconducting
+cavity was proposed adopting a quarter-wave beta=1 geometry. Based on the
+successful development of a proof-of-principle cavity, a HOM-damped 166.6 MHz
+compact superconducting cavity was subsequently designed. A ferrite damper was
+installed on the beam pipe to reduce HOM impedance below the stringent
+threshold of coupled-bunch instabilities. Being compact, RF field heating on
+the cavity vacuum seal was carefully examined against quenching the NbTi
+flange. The cavity was later dressed with a helium vessel and the tuning
+mechanism was also realized. Excellent RF and mechanical properties were
+eventually achieved. Finally, the two-cavity string was designed to ensure
+smooth transitions among components and proper shielding of synchrotron light.
+This paper presents a complete design of a fully dressed HOM-damped
+low-frequency beta=1 superconducting cavity for HEPS.",2109.06560v1
+2022-01-26,"Co-substituted BiFeO3: electronic, ferroelectric, and thermodynamic properties from first principles","Bismuth ferrite, BiFeO3, is a multiferroic solid that is attracting
+increasing attention as a potential photocatalytic material, because the
+ferroelectric polarisation enhances the separation of photogenerated carriers.
+With the motivation of finding routes to engineer the band gap and the band
+alignment, while conserving or enhancing the ferroelectric properties, we have
+investigated the thermodynamic, electronic and ferroelectric properties of
+BiCoxFe1 xO3 solid solutions, with 0 < x < 0.13, using density functional
+theory. We show that the band gap can be reduced from 2.9 eV to 2.1 eV by
+cobalt substitution, while simultaneously increasing the spontaneous
+polarisation, which is associated with a notably larger Born effective charge
+of Co compared to Fe cations. We discuss the interaction between Co impurities,
+which is strongly attractive and would drive the aggregation of Co, as
+evidenced by Monte Carlo simulations. Phase separation into a Co-rich phase is
+therefore predicted to be thermodynamically preferred, and the homogeneous
+solid solution can only exist in metastable form, protected by slow cation
+diffusion kinetics. Finally, we discuss the band alignment of pure and
+Co-substituted BiFeO3 with relevant redox potentials, in the context of its
+applicability in photocatalysis.",2201.11161v2
+2022-02-08,Kinetic Monte Carlo Modelling of Nano-oxide Precipitation and its Associated Stability under Neutron Irradiation for the Fe-Ti-Y-O system,"While developing nuclear materials, predicting their behavior under long-term
+irradiation regimes spanning decades poses a significant challenge. We
+developed a novel Kinetic Monte Carlo (KMC) model to explore the precipitation
+behavior of Y-Ti-O oxides along grain boundaries within nanostructured ferritic
+alloys (NFA). This model also assessed the response of the oxides to neutron
+irradiation, even up simulated radiation damage levels in the desired long dpa
+range for reactor components. Our simulations investigated how temperature and
+grain boundary sinks influenced the oxide characteristics of a 12YWT-like alloy
+during heat treatments at 1023 K, 1123 K, and 1223 K. The oxide characteristics
+observed in our simulations were in good agreement with existing literature.
+Furthermore, the impact of grain boundaries on precipitation was found to be
+minimal. The resulting oxide configurations and positions were used in
+subsequent simulations that exposed them to simulated neutron irradiation to a
+total accumulated dose of 8 dpa at three temperatures: 673 K, 773 K, and 873 K,
+and at dose rates of 10^(-3), 10^(-4), and 10^(-5) dpa/s. This demonstrated the
+expected inverse relationship between oxide size and dose rate. In a long-term
+irradiation simulation at 873 K and 10^(-3) dpa/s was taken out to 66 dpa and
+found the oxides in the vicinity of the grain boundary were more susceptible to
+dissolution. Additionally, we conducted irradiation simulations of a 14YWT-like
+alloy to reproduce findings from neutron irradiation experiments. The larger
+oxides in the 14YWT-like alloy did not dissolve and displayed stability similar
+to the experimental results.",2202.03641v3
+2022-02-18,Synergism between B and Nb improves fire resistance in microalloyed steels,"The development of new fire-resistant steels represents a challenge in
+materials science and engineering of utmost importance. Alloying elements such
+as Nb and Mo are generally used to improve the strength at both room- and
+high-temperatures due to, for example, the formation of precipitates and harder
+microconstituents. In this study we show alternatively that the addition of
+small amounts of boron in Nb-microalloyed steels may play a crucial role in
+maintaining the mechanical properties at high temperatures. The 66\,\%
+yield-strength criteria for fire resistance is achieved at $\approx
+574$\,{\deg}C for a boron steel, whereas without boron this value reaches
+$\approx 460$\,{\deg}C, a remarkable boron-induced mechanical strengthening
+enhancement. DFT calculations show that boron additions can lower the vacancy
+formation energy when compared to pure ferrite and, for Nb-B steels, there is a
+further 24\,\% reduction, suggesting that the boron-niobium combination acts as
+an effective pinning-based strengthening agent.",2202.09197v1
+2022-04-25,Multiscale modelling in nuclear ferritic steels: from nano-sized defects to embrittlement,"Radiation-induced embrittlement of nuclear steels is one of the main limiting
+factors for safe long-term operation of nuclear power plants. In support of
+accurate and safe reactor pressure vessel (RPV) lifetime assessments, we
+developed a physics-based model that predicts RPV steel hardening and
+subsequent embrittlement as a consequence of the formation of nano-sized
+clusters of minor alloying elements. This model is shown to provide reliable
+assessments of embrittlement for a very wide range of materials, with higher
+accuracy than industrial correlations. The core of our model is a multiscale
+modelling tool that predicts the kinetics of solute clustering, given the steel
+chemical composition and its irradiation conditions. It is based on the
+observation that the formation of solute clusters ensues from atomic transport
+driven by radiation-induced mechanisms, differently from classical
+nucleation-and-growth theories. We then show that the predicted information
+about solute clustering can be translated into a reliable estimate for
+radiation-induced embrittlement, via standard hardening laws based on the
+dispersed barrier model. We demonstrate the validity of our approach by
+applying it to hundreds of nuclear reactors vessels from all over the world.",2204.11441v1
+2022-05-17,Predicting failure characteristics of structural materials via deep learning based on nondestructive void topology,"Accurate predictions of the failure progression of structural materials is
+critical for preventing failure-induced accidents. Despite considerable
+mechanics modeling-based efforts, accurate prediction remains a challenging
+task in real-world environments due to unexpected damage factors and defect
+evolutions. Here, we report a novel method for predicting material failure
+characteristics that uniquely combines nondestructive X-ray computed tomography
+(X-CT), persistent homology (PH), and deep multimodal learning (DML). The
+combined method exploits the microstructural defect state at the time of
+material examination as an input, and outputs the failure-related properties.
+Our method is demonstrated to be effective using two types of fracture datasets
+(tensile and fatigue datasets) with ferritic low alloy steel as a
+representative structural material. The method achieves a mean absolute error
+(MAE) of 0.09 in predicting the local strain with the tensile dataset and an
+MAE of 0.14 in predicting the fracture progress with the fatigue dataset. These
+high accuracies are mainly due to PH processing of the X-CT images, which
+transforms complex and noisy three-dimensional X-CT images into compact
+two-dimensional persistence diagrams that preserve key topological features
+such as the internal void size, density, and distribution. The combined PH and
+DML processing of 3D X-CT data is our unique approach enabling reliable failure
+predictions at the time of material examination based on void topology
+progressions, and the method can be extended to various nondestructive failure
+tests for practical use.",2205.09075v1
+2022-07-31,Interface Engineering Enabled Low Temperature Growth of Magnetic Insulator on Topological Insulator,"Combining topological insulators (TIs) and magnetic materials in
+heterostructures is crucial for advancing spin-based electronics. Magnetic
+insulators (MIs) can be deposited on TIs using the spin-spray process, which is
+a unique non-vacuum, low-temperature growth process. TIs have highly reactive
+surfaces that oxidize upon exposure to atmosphere, making it challenging to
+grow spin-spray ferrites on TIs. In this work, it is demonstrated that a thin
+titanium capping layer on TI, followed by oxidation in atmosphere to produce a
+thin TiOx interfacial layer, protects the TI surface, without significantly
+compromising spin transport from the magnetic material across the TiOx to the
+TI surface states. First, it was demonstrated that in Bi2Te3/TiOx/Ni80Fe20
+heterostructures that TiOx provided an excellent barrier against diffusion of
+magnetic species, yet maintained a large spin-pumping effect. Second, the TiOx
+was also used as a protective capping layer on Bi2Te3, followed by the
+spin-spray growth of the MI, NixZnyFe2O4 (NZFO). For the thinnest TiOx
+barriers, Bi2Te3/TiOx/NZFO samples had AFM disordered interfacial layer because
+of diffusion. With increasing TiOx barrier thickness, the diffusion was
+reduced, but still maintained strong interfacial spin-pumping interaction.
+These experimental results demonstrate a novel method of low-temperature growth
+of magnetic insulators on TIs enabled by interface engineering.",2208.00499v1
+2022-08-09,Hybrid spin Hall nano-oscillators based on ferromagnetic metal/ferrimagnetic insulator heterostructures,"Spin-Hall nano-oscillators (SHNOs) are promising spintronic devices to
+realize current controlled GHz frequency signals in nanoscale devices for
+neuromorphic computing and creating Ising systems. However, traditional SHNOs
+-- devices based on transition metals -- have high auto-oscillation threshold
+currents as well as low quality factors and output powers. Here we demonstrate
+a new type of hybrid SHNO based on a permalloy (Py) ferromagnetic-metal
+nanowire and low-damping ferrimagnetic insulator, in the form of epitaxial
+lithium aluminum ferrite (LAFO) thin films. The superior characteristics of
+such SHNOs are associated with the excitation of larger spin-precession angles
+and volumes. We further find that the presence of the ferrimagnetic insulator
+enhances the auto-oscillation amplitude of spin-wave edge modes, consistent
+with our micromagnetic modeling. This hybrid SHNO expands spintronic
+applications, including providing new means of coupling multiple SHNOs for
+neuromorphic computing and advancing magnonics.",2208.04539v2
+2022-09-20,Modeling of 3D Printable Electrical Machineries Ferromagnetic Parts,"The electrical machinery core is formed with a ferromagnetic material that
+offers high magnetic properties. As ferromagnetic materials have high relative
+magnetic permeability, they are important in the formation of electromagnetic
+device cores. Conventional subtractive and powder metallurgy methods for
+fabrication electrical machineries offer significant core losses and reduce
+magnetic flux density and magnetic permeability. With the advancement of
+technology, the limitation of the traditional process can be overcome by using
+the additive manufacturing process. Hence, this paper proposes a 3D printable
+model of two types of single-phase transformers, referred to as E-I shape and
+U-I shape transformers respectively. Possibilities of designing the electrical
+machinery part which has a ferromagnetic core are investigated. The efficiency
+of the transformers is evaluated in terms of magnetic flux density distribution
+and volumetric loss density based on the results of a large number of Finite
+element simulation methods under various operating situations on COMSOL. The
+performance of various ferromagnetic materials such as Soft Iron (Fe) and
+Ferrite (Fe2O3) on the transformer core is evaluated. This analysis reveals
+that if U-I shaped transformer can be made from 3D printing, it will be the
+best feasible structure for higher operating frequency.",2209.09894v1
+2022-11-06,Cementron: Machine Learning the Constituent Phases in Cement Clinker from Optical Images,"Cement is the most used construction material. The performance of cement
+hydrate depends on the constituent phases, viz. alite, belite, aluminate, and
+ferrites present in the cement clinker, both qualitatively and quantitatively.
+Traditionally, clinker phases are analyzed from optical images relying on a
+domain expert and simple image processing techniques. However, the
+non-uniformity of the images, variations in the geometry and size of the
+phases, and variabilities in the experimental approaches and imaging methods
+make it challenging to obtain the phases. Here, we present a machine learning
+(ML) approach to detect clinker microstructure phases automatically. To this
+extent, we create the first annotated dataset of cement clinker by segmenting
+alite and belite particles. Further, we use supervised ML methods to train
+models for identifying alite and belite regions. Specifically, we finetune the
+image detection and segmentation model Detectron-2 on the cement microstructure
+to develop a model for detecting the cement phases, namely, Cementron. We
+demonstrate that Cementron, trained only on literature data, works remarkably
+well on new images obtained from our experiments, demonstrating its
+generalizability. We make Cementron available for public use.",2211.03223v1
+2022-12-16,Wideband Josephson Parametric Isolator,"The cryogenic hardware required to build a superconducting qubit based
+quantum computer demands a variety of microwave components. These elements
+include microwave couplers, filters, amplifiers, and circulators/isolators.
+Traditionally implemented as discrete components, integration of this
+peripheral hardware, in an effort to reduce overall footprint, thermal load,
+and added noise, is a key challenge to scaling modern quantum processors with
+qubit counts climbing over the 100+ mark. Ferrite--based microwave isolators,
+generally employed in the readout chain to decouple qubits and resonators from
+readout electronics, persist as one of the volumetrically largest devices still
+utilized as discrete components. Here we present an alternative two--port
+isolating integrated circuit derived from the DC Superconducting Quantum
+Interference Device (DC-SQUID). Non-reciprocal transmission is achieved using
+the three-wave microwave mixing properties of a flux-modulated DC--SQUID. We
+show that when multiple DC-SQUIDs are embedded in a multi--pole admittance
+inverting filter structure, the three-wave mixing derived from the flux pumping
+of the DC-SQUIDs can provide directional microwave power flow. For a
+three--pole filter device, we experimentally demonstrate a directionality
+greater than 15 dB over a 600 MHz bandwidth.",2212.08563v3
+2023-02-05,Origin of magnetically dead layers in spinel ferrites $M\text{Fe}_2\text{O}_4$ grown on $\text{Al}_2\text{O}_3$: Effects of post-deposition annealing studied by XMCD,"We study the electronic and magnetic states of as-grown and annealed
+$M\text{Fe}_2\text{O}_4$(111)/$\text{Al}_2\text{O}_3$(111) ($M=\text{Co, Ni}$)
+thin films with various thicknesses grown on Si(111) substrates with the
+$\gamma$-$\text{Al}_2\text{O}_3$(111) buffer layers by using x-ray absorption
+spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD), to investigate
+magnetically dead layers in these films. Although the magnetically dead layers
+in the as-grown samples are formed near the interface with the
+$\text{Al}_2\text{O}_3$ buffer layer, we reveal that ferrimagnetic order is
+partially recovered by post-deposition annealing at 973 K for 48 hours in air.
+By analyzing the line shapes of the XAS and XMCD spectra, we conclude that, in
+the dead layers, there are a significant number of vacancies at the $T_d$ sites
+of the spinel structure, which may be the microscopic origin of the degraded
+ferrimagnetic order in the $M\text{Fe}_2\text{O}_4$(111) thin films.",2302.02322v1
+2023-06-19,Transition between radial and toroidal orders in a trimer-based magnetic metasurface,"The change in the arrangement of magnetic dipole moments in a magnetic
+metasurface, due to the influence of an external static magnetic field, is
+discussed. Each meta-atom of the metasurface is composed of three identical
+disk-shaped resonators (trimer) made of magnetically saturated ferrite. To
+provide physical insight, full-wave numerical simulations of the near-fields
+and transmission characteristics of the metasurface are complemented by the
+theoretical description based on the multipole decomposition method. With these
+methods, the study of eigenmodes and scattering conditions of a single magnetic
+resonator, trimer, and their array forming the metasurface is performed. It is
+found that the magnetic dipole-based collective hybrid mode of the trimer can
+be gradually transformed from the radial (pseudomonopole) to azimuthal
+(toroidal) order and vice versa by varying the bias magnetic field strength.
+This is because the magnetic dipole moment of each individual disk constituting
+the trimer undergoes rotation as the bias magnetic field strength changes. This
+transition between two orders is accompanied by various patterns of
+localization of the electric field inside the meta-atoms. Due to the unique
+field configuration of these modes, the proposed metasurface can be considered
+for designing magnetic field sensors and nonreciprocal devices.",2306.10776v2
+2023-06-19,Ion Intercalation in Lanthanum Strontium Ferrite for Aqueous Electrochemical Energy Storage Devices,"Ion intercalation of perovskite oxides in liquid electrolytes is a very
+promising method for controlling their functional properties while storing
+charge, which opens the potential application in different energy and
+information technologies. Although the role of defect chemistry in the oxygen
+intercalation in a gaseous environment is well established, the mechanism of
+ion intercalation in liquid electrolytes at room temperature is poorly
+understood. In this study, the defect chemistry during ion intercalation of
+La0.5Sr0.5FeO3-{\delta} thin films in alkaline electrolytes is studied. Oxygen
+and proton intercalation into the LSF perovskite structure is observed at
+moderate electrochemical potentials (0.5 V to -0.4 V), giving rise to a change
+in the oxidation state of Fe (as a charge compensation mechanism). The
+variation of the concentration of holes as a function of the intercalation
+potential was characterized by in-situ ellipsometry and the concentration of
+electron holes was indirectly quantified for different electrochemical
+potentials. Finally, a dilute defect chemistry model that describes the
+variation of defect species during ionic intercalation was developed.",2306.10887v1
+2023-07-07,Dispersive Non-reciprocity between a Qubit and a Cavity,"The dispersive interaction between a qubit and a cavity is ubiquitous in
+circuit and cavity quantum electrodynamics. It describes the frequency shift of
+one quantum mode in response to excitations in the other, and in closed systems
+is necessarily bidirectional, i.e.~reciprocal. Here, we present an experimental
+study of a non-reciprocal dispersive-type interaction between a transmon qubit
+and a superconducting cavity, arising from a common coupling to dissipative
+intermediary modes with broken time reversal symmetry. We characterize the
+qubit-cavity dynamics, including asymmetric frequency pulls and photon
+shot-noise dephasing, under varying degrees of non-reciprocity by tuning the
+magnetic field bias of a ferrite component in situ. Furthermore, we show that
+the qubit-cavity dynamics is well-described in a wide parameter regime by a
+simple non-reciprocal master-equation model, which provides a compact
+description of the non-reciprocal interaction without requiring a full
+understanding of the complex dynamics of the intermediary system. Our result
+provides an example of quantum non-reciprocal phenomena beyond the typical
+paradigms of non-Hermitian Hamiltonians and cascaded systems.",2307.05298v3
+2023-08-01,Dose and compositional dependence of irradiation-induced property change in FeCr,"Ferritic/martensitic steels will be used as structural components in next
+generation nuclear reactors. Their successful operation relies on an
+understanding of irradiation-induced defect behaviour in the material. In this
+study, Fe and FeCr alloys (3-12%Cr) were irradiated with 20 MeV Fe-ions at 313
+K to doses ranging between 0.00008 dpa to 6.0 dpa. This dose range covers six
+orders of magnitude, spanning low, transition and high dose regimes. Lattice
+strain and hardness in the irradiated material were characterised with
+micro-beam Laue X-ray diffraction and nanoindentation, respectively.
+  Irradiation hardening was observed even at very low doses (0.00008 dpa) and
+showed a monotonic increase with dose up to 6.0 dpa. Lattice strain
+measurements of samples at 0.0008 dpa allow the calculation of equivalent
+Frenkel pair densities and corrections to the Norgett-Robinson-Torrens (NRT)
+model for Fe and FeCr alloys at low dose. NRT efficiency for FeCr is 0.2, which
+agrees with literature values for high irradiation energy. Lattice strain
+increases up to 0.8 dpa and then decreases when the damage dose is further
+increased. The strains measured in this study are lower and peak at a larger
+dose than predicted by atomistic simulations. This difference can be explained
+by taking temperature and impurities into account.",2308.00771v2
+2023-09-24,Approaching Ferrite-Based Exchange-Coupled Nanocomposites as Permanent Magnets,"During the past decade, CoFe2O4 (hard)/Co-Fe alloy (soft) magnetic
+nanocomposites have been routinely prepared by partial reduction of CoFe2O4
+nanoparticles. Monoxide (i.e., FeO or CoO) has often been detected as a
+byproduct of the reduction, although it remains unclear whether the formation
+of this phase occurs during the reduction itself or at a later stage. Here, a
+novel reaction cell was designed to monitor the reduction in situ using
+synchrotron powder X-ray diffraction (PXRD). Sequential Rietveld refinements of
+the in situ data yielded time-resolved information on the sample composition
+and confirmed that the monoxide is generated as an intermediate phase. The
+macroscopic magnetic properties of samples at different reduction stages were
+measured by means of vibrating sample magnetometry (VSM), revealing a magnetic
+softening with increasing soft phase content, which was too pronounced to be
+exclusively explained by the introduction of soft material in the system. The
+elemental compositions of the constituent phases were obtained from joint
+Rietveld refinements of ex situ high-resolution PXRD and neutron powder
+diffraction (NPD) data. It was found that the alloy has a tendency to emerge in
+a Co-rich form, inducing a Co deficiency on the remaining spinel phase, which
+can explain the early softening of the magnetic material.",2309.13729v1
+2023-09-26,Multiferroic Magnon Spin-Torque Based Reconfigurable Logic-In-Memory,"Magnons, bosonic quasiparticles carrying angular momentum, can flow through
+insulators for information transmission with minimal power dissipation.
+However, it remains challenging to develop a magnon-based logic due to the lack
+of efficient electrical manipulation of magnon transport. Here we present a
+magnon logic-in-memory device in a spin-source/multiferroic/ferromagnet
+structure, where multiferroic magnon modes can be electrically excited and
+controlled. In this device, magnon information is encoded to ferromagnetic bits
+by the magnon-mediated spin torque. We show that the ferroelectric polarization
+can electrically modulate the magnon spin-torque by controlling the
+non-collinear antiferromagnetic structure in multiferroic bismuth ferrite thin
+films with coupled antiferromagnetic and ferroelectric orders. By manipulating
+the two coupled non-volatile state variables (ferroelectric polarization and
+magnetization), we further demonstrate reconfigurable logic-in-memory
+operations in a single device. Our findings highlight the potential of
+multiferroics for controlling magnon information transport and offer a pathway
+towards room-temperature voltage-controlled, low-power, scalable magnonics for
+in-memory computing.",2309.14614v1
+2023-09-24,Dense strontium hexaferrite-based permanent magnet composites assisted by cold sintering process,"The use of rare-earth-based permanent magnets is one of the critical points
+for the development of the current technology. On the one hand, industry of the
+rare-earths is highly polluting due to the negative environmental impact of
+their extraction and, on the other hand, the sector is potentially dependent on
+China. Therefore, investigation is required both in the development of
+rare-earth-free permanent magnets and in sintering processes that enable their
+greener fabrication with attractive magnetic properties at a more competitive
+price. This work presents the use of a cold sintering process (CSP) followed by
+a post-annealing at 1100 {\deg}C as a new way to sinter composite permanent
+magnets based on strontium ferrite (SFO). Composites that incorporate a
+percentage < 10% of an additional magnetic phase have been prepared and the
+morphological, structural and magnetic properties have been evaluated after
+each stage of the process. CSP induces a phase transformation of SFO in the
+composites, which is partially recovered by the post-thermal treatment
+improving the relative density to 92% and the magnetic response of the final
+magnets with a coercivity of up to 3.0 kOe. Control of the magnetic properties
+is possible through the composition and the grain size in the sintered magnets.
+These attractive results show the potential of the sintering approach as an
+alternative to develop modern rare-earth-free composite permanent magnets.",2309.16038v1
+2023-10-13,Optimizing site-specific specimen preparation for Atom Probe Tomography by using hydrogen for visualizing radiation-induced damage,"Atom probe tomography (APT) is extensively used to measure the local
+chemistry of materials. Site-specific preparation via a focused ion beam (FIB)
+is routinely implemented to fabricate needle-shaped specimens with an end
+radius in the range of 50 nm. This preparation route is sometimes supplemented
+by transmission Kikuchi diffraction (TKD) to facilitate the positioning of a
+region of interest sufficiently close to the apex. Irradiating the specimen
+with energetic electrons and ions can lead to the generation of vacancies and
+even amorphization of the specimen. These extrinsically created vacancies
+become crucial for probing the hydrogen or deuterium distribution since they
+act as a strong trap. Here, we investigated the feasibility of site-specific
+preparation of a two-phase medium-Mn steel containing austenite (fcc) and
+ferrite (bcc). Following gaseous charging of APT specimens in deuterium (D2),
+clusters enriched by up to 35 at.% D, are imaged after Pt deposition,
+conventional Ga-FIB preparation, and TKD conducted separately. These D-rich
+clusters are assumed to arise from the agglomeration of vacancies acting as
+strong traps. By systematically eliminating these preparation-induced damages,
+we finally introduce a workflow allowing for studying intrinsic traps for H/D
+inherent to the material.",2310.09120v1
+2023-12-25,Superplasticity-like behavior of ultrafine-grained austenitic steel 321,"Hot rolled commercial metastable austenitic steel 321 with strongly elongated
+thin delta-ferrite particles in its microstructure was the object of
+investigations. Ultrafine-grained (UFG) microstructure in steel 321 was formed
+by Equal Channel Angular Pressing (ECAP) at 150 oC and 450 oC. When heating the
+UFG steel specimens, the nucleation of sigma-phase particles blocking the grain
+boundary migration was observed. The maximum elongation to failure (~250%) was
+achieved at the deformation temperature 750 oC. The process of superplastic
+deformation of the UFG steel 321 is controlled by simultaneous grain boundary
+sliding and power-law creep. The contribution of each process depends on the
+grain growth rate in the superplasticity regime as well as on defect
+accumulation on the grain boundaries. The fracture of the UFG steel 321
+specimens has a cavitational character - an intensive formation of large
+elongated pores at the non-metallic particles as well as of the submicron pores
+at the sigma-phase particles in the course of superplastic deformation were
+observed.",2312.15785v1
+2024-01-02,"Automated Segmentation of Large Image Datasets using Artificial Intelligence for Microstructure Characterisation, Damage Analysis and High-Throughput Modelling Input","Many properties of commonly used materials are driven by their
+microstructure, which can be influenced by the composition and manufacturing
+processes. To optimise future materials, understanding the microstructure is
+critically important. Here, we present two novel approaches based on artificial
+intelligence that allow the segmentation of the phases of a microstructure for
+which simple numerical approaches, such as thresholding, are not applicable:
+One is based on the nnU-Net neural network, and the other on generative
+adversarial networks (GAN). Using large panoramic scanning electron microscopy
+images of dual-phase steels as a case study, we demonstrate how both methods
+effectively segment intricate microstructural details, including martensite,
+ferrite, and damage sites, for subsequent analysis. Either method shows
+substantial generalizability across a range of image sizes and conditions,
+including heat-treated microstructures with different phase configurations. The
+nnU-Net excels in mapping large image areas. Conversely, the GAN-based method
+performs reliably on smaller images, providing greater step-by-step control and
+flexibility over the segmentation process. This study highlights the benefits
+of segmented microstructural data for various purposes, such as calculating
+phase fractions, modelling material behaviour through finite element
+simulation, and conducting geometrical analyses of damage sites and the local
+properties of their surrounding microstructure.",2401.01147v3
+2024-01-26,Engineering strong magnetoelectricity using a hexagonal 2D material on electron-doped hexagonal LuFeO$_3$,"Cubic perovskite-structure ABO$_3$ and A$_{1-x}$A$^{\prime}$$_x$BO$_3$-type
+oxides have been investigated extensively while their hexagonal-structure
+versions have received minimal attention, even though they are multiferroic and
+can form heterostructures with the manifold hexagonal two-dimensional
+materials. Hexagonal ferrites of the form RFeO$_3$, where R is yttrium or a
+rare-earth element such as Lu, Yb, etc., feature coupled ferroelectricity (FE)
+and weak-ferromagnetism (wFM), exhibiting linear magnetoelectricity. Their only
+drawback is weak ferromagnetism. In this paper, we employ
+density-functional-theory (DFT) calculations on hexagonal LuFeO$_3$ ($h$-LFO),
+targeting its magnetic ordering by electron doping,anticipating
+spin-disproportionation of the Fe sublattices. Indeed, we show that
+spin-disproportionation in heavily-electron-doped versions
+Lu$_{1-x}$Hf$_x$FeO$_3$ ($h$-LHFO), especially for x=1/3 and 1/2, leads to
+robust out-of-plane collinear ferrimagnetism that is stable at room
+temperature. Furthermore, the robust ferroelectricity of $h$-LFO persists via a
+Jahn-Teller metal-to-insulator transition. Finally, we construct a
+$h$-LHFO/$h$-2D heterostructure, where $h$-2D stands for the FE/FM monolayer
+MnSTe, and demonstrate strong magnetoelectric coupling, namely manipulation of
+magnetic skyrmions in MnSTe by an external electric field through the $h$-LHFO
+polarization, opening up a new realm for magnetoelectric applications.",2401.15053v1
+2010-08-18,Contraction and expansion effects on the substitution-defect properties of thirteen alloying elements in bcc Fe,"Proposed as blanket structural materials for fusion power reactors, reduced
+activation ferritic/martensitic (RAFM) steel undergoes volume expanding and
+contracting in a cyclic mode under service environment. Particularly, being
+subjected to significant fluxes of fusion neutrons RAFM steel suffers
+considerable local volume variations in the radiation damage involved regions.
+It is necessary to study the structure properties of the alloying elements in
+contraction and expansion states. In this paper we studied local substitution
+structures of thirteen alloying elements Al, Co, Cr, Cu, Mn, Mo, Nb, Ni, Si,
+Ta, Ti, V, and W in bcc Fe and calculated their substitutional energies in the
+volume variation range from -1.0% to 1.0%. From the structure relaxation
+results of the first five neighbor shells around the substitutional atom we
+find the relaxation in each neighbor shell keeps approximately uniform within
+the volume variation from -1.0% to 1.0% except those of Mn and the relaxation
+of the fifth neighbor shell is stronger than that of the third and forth,
+indicating that the lattice distortion due to the substitution atom is easier
+to spread in <111> direction than in other direction. The relaxation pattern
+and intensity are related to the size and electron structure of the
+substitutional atom. For some alloying elements, such as Mo, Nb, Ni, Ta, Ti and
+W, the substitutional energy decreases noticeably when the volume increases.
+Further analysis show that the substitutional energy comprises the energy
+variation originated from local structure relaxation and the chemical potential
+difference of the substitutional atom between its elemental crystalline state
+and the solid solution phase in bcc Fe. We think the approximately uniform
+relaxation of each neighbor shell around a substitutional atom give rise to a
+linear decrease in the substitutional energy with the increasing volume.",1008.3001v1
+2014-07-30,Transition metal solute interactions with point defects in austenitic iron from first principles,"We present a comprehensive set of first principles electronic structure
+calculations to study transition metal solutes and their interactions with
+point defects in austenite. Clear trends were observed across the series.
+Solute-defect interactions were strongly correlated to the solute size factors,
+consistent with local strain field effects. Strong correlations with results in
+ferrite show insensitivity to the underlying crystal structure in Fe. Oversized
+solutes act as strong traps for vacancy and self-interstitial defects and as
+nucleation sites for the development of proto-voids and small self-interstitial
+loops. The reduction in defect mobility and net defect concentrations explains
+the observed radiation-damage resistance in austenitic steels doped with
+oversized solutes. Oversized solutes remaining dissolved in oxide
+dispersion-strengthened (ODS) steels could contribute to their radiation-damage
+resistance. Ni and Co diffuse more slowly than Fe, along with any vacancy flux
+produced under irradiation below a critical temperature, which is 400 K for Co
+and their concentrations should be enhanced at defect sinks. Cr and Cu diffuse
+more quickly than Fe, against a vacancy flux and will be depleted at defect
+sinks. Oversized solutes early in the transition metal series form
+highly-stable solute-centred divacancy (SCD) defects with a nearest-neighbour
+vacancy. The vacancy-mediated diffusion of these solutes is dominated by the
+dissociation and reassociation of the SCDs, with a lower activation energy than
+for self-diffusion, which has important implications for the nucleation and
+growth of complex oxide nanoparticles containing these solutes in ODS steels.
+Interstitial-mediated solute diffusion is energetically disfavoured for all
+except Cr, Mn, Co and Ni. The central role that solute size plays in the
+results presented here means they should apply to other solvent metals and
+alloys.",1407.7996v1
+2015-09-30,Roadmap for Emerging Materials for Spintronic Device Applications,"The Technical Committee of the IEEE Magnetics Society has selected 7 research
+topics to develop their roadmaps, where major developments should be listed
+alongside expected timelines; (i) hard disk drives, (ii) magnetic random access
+memories, (iii) domain-wall devices, (iv) permanent magnets, (v) sensors and
+actuators, (vi) magnetic materials and (vii) organic devices. Among them,
+magnetic materials for spintronic devices have been surveyed as the first
+exercise. In this roadmap exercise, we have targeted magnetic tunnel and
+spin-valve junctions as spintronic devices. These can be used for example as a
+cell for a magnetic random access memory and spin-torque oscillator in their
+vertical form as well as a spin transistor and a spin Hall device in their
+lateral form. In these devices, the critical role of magnetic materials is to
+inject spin-polarised electrons efficiently into a non-magnet. We have
+accordingly identified 2 key properties to be achieved by developing new
+magnetic materials for future spintronic devices: (1) Half-metallicity at room
+temperature (RT); (2) Perpendicular anisotropy in nano-scale devices at RT. For
+the first property, 5 major magnetic materials are selected for their
+evaluation for future magnetic/spintronic device applications: Heusler alloys,
+ferrites, rutiles, perovskites and dilute magnetic semiconductors. These alloys
+have been reported or predicted to be half-metallic ferromagnets at RT. They
+possess a bandgap at the Fermi level EF only for its minority spins, achieving
+100% spin polarisation at EF. We have also evaluated L10-alloys and
+D022-Mn-alloys for the development of a perpendicularly anisotropic ferromagnet
+with large spin polarisation. We have listed several key milestones for each
+material on their functionality improvements, property achievements, device
+implementations and interdisciplinary applications within 35 years time scale.",1509.08997v1
+2019-05-10,Experimental Implementations of Cavity-Magnon Systems: from Ultra Strong Coupling to Applications in Precision Measurement,"Several experimental implementations of cavity-magnon systems are presented.
+First an Yttrium Iron Garnet (YIG) block is placed inside a re-entrant cavity
+where the resulting hybrid mode is measured to be in the ultra strong coupling
+regime. When fully hybridised the ratio between the coupling rate and uncoupled
+mode frequencies is determined to be $g/\omega=0.46$. Next a thin YIG cylinder
+is placed inside a loop gap cavity. The bright mode of this cavity couples to
+the YIG sample and is similarly measured to be in the ultra strong coupling
+regime with ratio of coupling rate to uncoupled mode frequencies as
+$g/\omega=0.34$. A larger spin density medium such as lithium ferrite (LiFe) is
+expected to improve couplings by a factor of 1.46 in both systems as coupling
+strength is shown to be proportional to the square root of spin density and
+magnetic moment. Such strongly coupled systems are potentially useful for
+cavity QED, hybrid quantum systems and precision dark matter detection
+experiments. The YIG disc in the loop gap cavity, is, in particular, shown to
+be a strong candidate for dark matter detection. Finally, a LiFe sphere inside
+a two post re-entrant cavity is considered. In past work it was shown that the
+magnon mode in the sample has a turnover point in frequency. Additionally, it
+was predicted that if the system was engineered such that it fully hybridised
+at this turnover point the cavity-magnon polariton (CMP) transition frequency
+would become insensitive to both first and second order magnetic bias field
+fluctuations, a result useful for precision frequency applications. This work
+implements such a system by engineering the cavity mode frequency to near this
+turnover point, with suppression in sensitivity to second order bias magnetic
+field fluctuations shown.",1905.04002v2
+2020-07-21,Atom probe characterisation of segregation driven Cu and Mn-Ni-Si co-precipitation in neutron irradiated T91 tempered-martensitic steel,"The T91 grade and similar 9Cr tempered-martensitic steels (also known as
+ferritic-martensitic) are leading candidate structural alloys for fast fission
+nuclear and fusion power reactors. At low temperatures (300 to 400 $^\circ$C)
+neutron irradiation hardens and embrittles these steels, therefore it is
+important to investigate the origin of this mode of life limiting property
+degradation. T91 steel specimens were separately neutron irradiated to 2.14 dpa
+at 327 $^\circ$C and 8.82 dpa at 377 $^\circ$C in the Idaho National Laboratory
+Advanced Test Reactor. Atom probe tomography was used to investigate the
+segregation driven formation of Mn-Ni-Si-rich (MNSPs) and Cu-rich (CRP)
+co-precipitates. The precipitates increase in size and, slightly, in volume
+fraction at the higher irradiation temperature and dose, while their
+corresponding compositions were very similar, falling near the Si(Mn,Ni) phase
+field in the Mn-Ni-Si projection of the Fe-based quaternary phase diagram.
+While the structure of the precipitates has not been characterized, this
+composition range is distinctly different than that of the typically cited
+G-phase. The precipitates are composed of CRP with MNSP appendages. Such
+features are often observed in neutron irradiated reactor pressure vessel (RPV)
+steels. However, the Si, Ni, Mn, P and Cu solutes concentrations are lower in
+the T91 than in typical RPV steels. Thus, in T91 precipitation primarily takes
+place in solute segregated regions of line and loop dislocations. These results
+are consistent with the model for radiation induced segregation driven
+precipitation of MNSPs proposed by Ke et al. Cr-rich alpha prime ($\alpha$')
+phase formation was not observed.",2007.10710v1
+2018-05-16,"Single Crystal Permanent Magnet: Extraordinary Magnetic Behavior in the ta, Cu and Fe Substituted CeCo5 System","To reduce material and processing costs of commercial permanent magnets and
+to attempt to fill the empty niche of energy products, 10 - 20 MGOe, between
+low-flux (ferrites, alnico) and high-flux (Nd2Fe14B- and SmCo5-type) magnets,
+we report synthesis, structure, magnetic properties and modeling of Ta, Cu and
+Fe substituted CeCo5. Using a self-flux technique, we grew single crystals of I
+- Ce15.1Ta1.0Co74.4Cu9.5, II - Ce16.3Ta0.6Co68.9Cu14.2, III -
+Ce15.7Ta0.6Co67.8Cu15.9, IV - Ce16.3Ta0.3Co61.7Cu21.7 and V -
+Ce14.3Ta1.0Co62.0Fe12.3Cu10.4. X-ray diffraction analysis (XRD) showed that
+these materials retain a CaCu5 substructure and incorporate small amounts of Ta
+in the form of \dumb-bells"", filling the 2e crystallographic sites within the
+1D hexagonal channel with the 1a Ce site, whereas Co, Cu and Fe are
+statistically distributed among the 2c and 3g crystallographic sites. Scanning
+electron microscopy, energy dispersive X-ray spectroscopy (SEM-EDS) and
+scanning transmission electron microscopy (STEM) examinations provided strong
+evidence of the single-phase nature of the as-grown crystals, even though they
+readily exhibited significant magnetic coercivitie of ~1.6 - ~1.8 kOe caused by
+Co-enriched, nano-sized, structural defects and faults that can serve as
+pinning sites. Formation of the ""composite crystal"" during the heat treatment
+creates a 3D array of extended defects within a primarily single grain single
+crystal, which greatly improves its magnetic characteristics. Possible causes
+of the formation of the ""composite crystal"" may be associated with Ta atoms
+leaving matrix interstices at lower temperatures and/or matrix degradation
+induced by decreased miscibility at lower temperatures. Fe strongly improves
+both the Curie temperature and magnetization of the system resulting in
+(BH)max:~13 MGOe at room temperature.",1805.06545v1
+2016-12-28,57Fe Mössbauer study of unusual magnetic structure of multiferroic 3R-AgFeO2,"We report new results of a 57Fe M\""ossbauer study of multiferroic 3R-AgFeO2
+powder samples performed in a wide temperature range, including two points, TN1
+~ 14 K and TN2 ~ 9 K, of magnetic phase transitions. At the intermediate
+temperature range, TN2 < T < TN1, the 57Fe M\""ossbauer spectra can be described
+in terms of collinear spin-density-waves (SDW) with the inclusion of many
+high-order harmonics, indicating that the real magnetic structure of this
+ferrite appears to be more complicated than a pure sinusoidally modulated SDW.
+The spectra at low temperatures, T < TN2, consist of a Zeeman pattern with line
+broadenings and sizeable spectral asymmetry. It has been shown that the
+observed spectral shape is consistent with a transition to the elliptical
+cycloidal magnetic structure. An analysis of the experimental spectra was
+carried out under the assumption that the electric hyperfine interactions are
+modulated when the Fe3+ magnetic moment rotates with respect to the principal
+axis of the EFG tensor and emergence of the strong anisotropy of the magnetic
+hyperfine field Hhf at the 57Fe nuclei. The large and temperature-independent
+anharmonicity parameter, m ~ 0.78, of the cycloidal spin structure obtained
+from the experimental spectra results from easy-axis anisotropy in the plane of
+rotation of the iron spin. Analysis of different mechanisms of spin and
+hyperfine interactions in 3R-AgFeO2 and its structural analogue CuFeO2 points
+to a specific role played by the topology of the exchange coupling and the
+oxygen polarization in the delafossite structures.",1612.08926v4
+2019-10-11,"Low-Damping Ferromagnetic Resonance in Electron-Beam Patterned, High-$Q$ Vanadium Tetracyanoethylene Magnon Cavities","Integrating patterned, low-loss magnetic materials into microwave devices and
+circuits presents many challenges due to the specific conditions that are
+required to grow ferrite materials, driving the need for flip-chip and other
+indirect fabrication techniques. The low-loss ($\alpha = 3.98 \pm 0.22 \times
+10^{-5}$), room-temperature ferrimagnetic coordination compound vanadium
+tetracyanoethylene ($\mathrm{V[TCNE]}_x$) is a promising new material for these
+applications that is potentially compatible with semiconductor processing. Here
+we present the deposition, patterning, and characterization of
+$\mathrm{V[TCNE]}_x$ thin films with lateral dimensions ranging from 1 micron
+to several millimeters. We employ electron-beam lithography and liftoff using
+an aluminum encapsulated poly(methyl methacrylate), poly(methyl
+methacrylate-methacrylic acid) copolymer bilayer (PMMA/P(MMA-MAA)) on sapphire
+and silicon. This process can be trivially extended to other common
+semiconductor substrates. Films patterned via this method maintain low-loss
+characteristics down to 25 microns with only a factor of 2 increase down to 5
+microns. A rich structure of thickness and radially confined spin-wave modes
+reveals the quality of the patterned films. Further fitting, simulation, and
+analytic analysis provides an exchange stiffness, $A_{ex} = 2.2 \pm 0.5 \times
+10^{-10}$ erg/cm, as well as insights into the mode character and surface spin
+pinning. Below a micron, the deposition is non-conformal, which leads to
+interesting and potentially useful changes in morphology. This work establishes
+the versatility of $\mathrm{V[TCNE]}_x$ for applications requiring highly
+coherent magnetic excitations ranging from microwave communication to quantum
+information.",1910.05325v1
+2019-03-21,Quantitative magneto-optical imaging with ferrite garnets,"Magneto-optical imaging is a powerful technique for studying qualitative
+features of magnetic flux distributions in superconductors and other magnetic
+samples. However, magneto-optical imaging does not automatically return
+two-dimensional maps with the actual values of the magnetic field, due to the
+non-linear response functions of magneto-optical indicator films and in
+practice also non-uniform illumination. A quantitative treatment is needed in
+order to achieve such a calibration. After calibration, one can proceed to
+deduce the corresponding two-dimensional maps of the current density
+distribution from inversion of the Biot-Savart law. While there has been
+published a large amount of work on quantitative magneto-optical imaging, the
+material is scattered and notation differs significantly between different
+authors. These notes originate from parts of the Ph. D. thesis of the author
+and collect the most important materials into a unified and updated treatment.
+Basic aspects of magnetic flux penetration in superconductors including the
+Bean model are reviewed briefly in chapter 1. In chapter 2, the method of
+magneto-optical imaging using the Faraday effect is introduced, together with
+practical aspects of magneto-optical experiments at low temperatures and the
+semi-qualitative technique of RGB addition for checking the reproducibility of
+flux patterns. The physics of magneto-optical indicator films and calibration
+of magneto-optical images into maps of magnetic field values are discussed in
+chapter 3. Next, in chapter 4 the Biot-Savart law and fast Fourier
+transformations are discussed before proceeding to inversion of magnetic field
+maps into current density maps. Finally, magnetometry with Faraday
+magneto-optical imaging is treated. MATLAB codes for several of the discussed
+concepts can be found at https://github.com/atlejq/Magneto-optics",1903.09130v1
+2020-06-25,"Influence of Yb3+on the structural, electrical and optical properties of sol-gel synthesized Ni-Zn nanoferrites","Polycrystalline Yb substituted NiZn nanoferrites with the compositions of
+Ni0.5Zn0.5YbxFe2-xO4 (x= 0.00, 0.04, 0.08, 0.12, 0.16 and 0.20) have been
+synthesized using sol gel auto combustion technique. Single phase cubic spinel
+structure has been confirmed by the X ray diffraction (XRD) patterns. Larger
+lattice constants of the compositions are found with increasing Yb3+
+concentration while the average grain size (52 to 18 nm) has noticeable
+decrease as Yb3+ content is increased. The presence of all existing elements as
+well as the purity of the samples has also been confirmed from energy
+dispersive X ray spectroscopic (EDS) analysis. Frequency dependent dielectric
+constant, dielectric loss, dielectric relaxation time, AC and DC resistivity of
+the compositions have also been examined at room temperature. The DC
+resistivity value is found in the order of 10 to power 10 (omega-cm) which is
+at least four orders greater than the ferrites prepared by conventional method.
+This larger value of resistivity attributes due to very small grain size and
+successfully explained using the Verwey and deBoer hopping conduction model.
+The contribution of grain and grain boundary resistance has been elucidated
+using Cole Cole plot. The study of temperature dependent DC resistivity
+confirms the semiconducting nature of all titled compositions wherein bandgap
+(optical) increases from 2.73 eV to 3.25 eV with the increase of Yb content.
+The high value of resistivity is of notable achievement for the compositions
+that make them a potential candidate for implication in the high frequency
+applications where reduction of eddy current loss is highly required.",2006.14180v1
+2021-09-06,Critical State Theory For The Magnetic Coupling Between Soft Ferromagnetic Materials And Type-II Superconductors,"Improving our understanding of the physical coupling between type-II
+superconductors (SC) and soft ferromagnetic materials (SFM), is root for
+progressing onto the application of SC-SFM metastructures in scenarios such as
+magnetic cloaking, magnetic shielding, and power transmission systems. However,
+in the latter some intriguing and yet unexplained phenomena occurred, such as a
+noticeable rise in the SC energy losses, and a local but not isotropic
+deformation of its magnetic flux density. These phenomena, which are in
+apparent contradiction with the most fundamental theory of electromagnetism for
+superconductivity, i.e., the critical state theory (CST), have remained
+unexplained for about 20 years, given place to the acceptance of the
+controversial and yet paradigmatic existence of the so-called overcritical
+current densities. Therefore, aimed to resolve these long-standing problems, we
+extended the CST by incorporating a semi-analytical model for cylindrical
+monocore SC-SFM heterostructures, setting the standards for its validation with
+a variational approach of multipole functionals for the magnetic coupling
+between Sc and SFM materials. It is accompanied by a comprehensive numerical
+study for SFM sheaths of arbitrary dimensions and magnetic relative
+permeabilities $\mu_{r}$, ranging from $\mu_{r}=5$ (NiZn ferrites) to
+$\mu_{r}=350000$ (pure Iron), showing how the AC-losses of the SC-SFM
+metastructure radically changes as a function of the SC and the SFM radius for
+$\mu_{r} \geq 100$. Our numerical technique and simulations revealed also a
+good qualitative agreement with the magneto optical imaging observations that
+were questioning the CST validness, proving therefore that the reported
+phenomena for self-field SC-SFM heterostructures can be understood without
+including the ansatz of overcritical currents.",2109.02604v2
+2021-11-12,"Implementing and evaluating far-field 3D X-ray diffraction at the I12 JEEP beamline, Diamond Light Source","Three-dimensional X-ray diffraction (3DXRD) is shown to be feasible at the
+I12 Joint Engineering, Environmental and Processing (JEEP) beamline of Diamond
+Light Source. As a demonstration, a microstructually simple low-carbon ferritic
+steel was studied in a highly textured and annealed state. A processing
+pipeline suited to this beamline was created, using software already
+established in the 3DXRD user community, enabling grain centre-of-mass
+positions, orientations and strain tensor elements to be determined.
+Orientations, with texture measurements independently validated from electron
+backscatter diffraction (EBSD) data, possessed a $\sim 0.1^\circ$ uncertainty,
+comparable with other 3DXRD instruments. The spatial resolution was limited by
+the far-field detector pixel size; the average of the grain centre of mass
+position errors was determined as $\pm \sim 80 \mu$m. An average per-grain
+error of $\sim 1 \times 10^{-3}$ for the elastic strains was also measured;
+this could be reduced in future experiments by improving sample preparation,
+data collection and analysis techniques. Application of 3DXRD onto I12 shows
+great potential, where its implementation is highly desirable due the flexible,
+open architecture of the beamline. User-owned or designed sample environments
+can be used, thus 3DXRD could be applied to previously unexplored scientific
+areas.",2111.06779v2
+2022-11-17,On the critical role of martensite hardening behavior in the paradox of local and global ductility in dual-phase steels,"Experimental findings in the literature reveal that DP steels with identical
+strength and composition, but different microstructures, exhibit inconsistent
+trends under either necking-controlled or damage-controlled ductility tests. A
+special case of this phenomenon is referred to in the forming community as the
+cut-edge failure or edge cracking issue of DP steels. It is observed that
+globally ductile microstructures are prone to premature damage at cut edges
+while a comparatively less ductile DP steel performs better under the locally
+applied deformation at such edges. In this paper, a systematical statistical
+study is conducted to analyse this paradox from a micromechanical point of
+view. The obtained results qualitatively confirm the experimental observations
+and allowed us to explain/rationalize them, as follows. To reach a higher
+necking-controlled ductility, i.e. global ductility, the mechanical contrast
+between ferrite and martensite must be increased. Since martensite reveals a
+very high initial hardening and fast saturation, activation of martensite
+plasticity will lead to early necking in the microstructure and should
+therefore be avoided; a high mechanical phase contrast has this effect.
+However, at the same time a higher mechanical phase contrast is detrimental for
+the local ductility. More heterogeneity in the microstructure causes the
+generation of higher local plastic strains and triaxial stresses which leads to
+early damages. Therefore, in DP steel, increasing the global ductility may come
+at the expense of decreasing local ductility, and vice versa. The martensite
+hardening behavior is the main factor governing this phenomenon, and therefore
+also constitutes the key to processing improved steels that combine the best of
+both.",2211.09720v1
+2023-02-24,Nuclear quadrupole resonance spectroscopy with a femtotesla diamond magnetometer,"Sensitive Radio-Frequency (RF) magnetometers that can detect oscillating
+magnetic fields at the femtotesla level are needed for demanding applications
+such as Nuclear Quadrupole Resonance (NQR) spectroscopy. RF magnetometers based
+on Nitrogen-Vacancy (NV) centers in diamond have been predicted to offer
+femtotesla sensitivity, but published experiments have largely been limited to
+the picotesla level. Here, we demonstrate a femtotesla RF magnetometer based on
+an NV-doped diamond membrane inserted between two ferrite flux concentrators.
+The device operates in bias magnetic fields of 2-10 microtesla and provides a
+~300-fold amplitude enhancement within the diamond for RF magnetic fields in
+the 0.07-3.6 MHz range. The magnetometer's sensitivity is ~70 fT s^{1/2} at
+0.35 MHz, and the noise floor decreases to below 2 fT after 1 hour of
+acquisition. We used this sensor to detect the 3.6 MHz NQR signal of 14N in
+sodium nitrite powder at room temperature. NQR signals are amplified by a
+resonant RF coil wrapped around the sample, allowing for higher signal-to-noise
+ratio detection. The diamond RF magnetometer's recovery time after a strong RF
+pulse is ~35 us, limited by the coil ring-down time. The sodium-nitrite NQR
+frequency shifts linearly with temperature as -1.00 +/- 0.02 kHz/K, the
+magnetization dephasing time is T2* = 887 +/- 51 us, and a spin-lock spin-echo
+pulse sequence extends the signal lifetime to 332 +/- 23 ms, all consistent
+with coil-based NQR studies. Our results expand the sensitivity frontier of
+diamond magnetometers to the femtotesla range, with potential applications in
+security, medical imaging, and materials science.",2302.12401v1
+2023-04-05,A Checklist to Publish Collections as Data in GLAM Institutions,"Large-scale digitization in Galleries, Libraries, Archives and Museums (GLAM)
+created the conditions for providing access to collections as data. It opened
+new opportunities to explore, use and reuse digital collections. Strong
+proponents of collections as data are the Innovation Labs which provided
+numerous examples of publishing datasets under open licenses in order to reuse
+digital content in novel and creative ways. Within the current transition to
+the emerging data spaces, clouds for cultural heritage and open science, the
+need to identify practices which support more GLAM institutions to offer
+datasets becomes a priority, especially within the smaller and medium-sized
+institutions.
+  This paper answers the need to support GLAM institutions in facilitating the
+transition into publishing their digital content and to introduce collections
+as data services; this will also help their future efficient contribution to
+data spaces and cultural heritage clouds. It offers a checklist that can be
+used for both creating and evaluating digital collections suitable for
+computational use. The main contributions of this paper are i) a methodology
+for devising a checklist to create and assess digital collections for
+computational use; ii) a checklist to create and assess digital collections
+suitable for use with computational methods; iii) the assessment of the
+checklist against the practice of institutions innovating in the Collections as
+data field; and iv) the results obtained after the application and
+recommendations for the use of the checklist in GLAM institutions.",2304.02603v2
+2023-06-13,"Noise and Thermal Performance of a Sub-Attofarad Capacitance Sensor for Precision Measurements, with Applications in Gravitational Wave Detectors","We describe the design principles, fabrication, and characterization of a
+precision AC resonant capacitance bridge (RCB) sensor, based on a resonant
+differential planar printed circuit board transformer with a solid (ungapped)
+MnZn ferrite core, demonstrating a short-term sensitivity at 293 K of 0.225 +/-
+0.005 aF/rtHz, at around 120 kHz resonance frequency and 1 Hz Fourier
+measurement frequency. At 120 K the RCB short term noise sensitivity is 0.118
++/- 0.005 aF/rtHz. We compare the ungapped configuration to five different
+RCBs; three with a core gap of 65 um and two with a core gap of 130 um. Their
+average room temperature short term noise sensitivities are 0.30 +/- 0.01
+aF/rtHz and 0.45 +/- 0.01 aF/rtHz, while the cryogenic operation of these
+transformers at 120 K resulted in averaged sensitivities of 0.23 +/- 0.01
+aF/rtHz and of 0.36 +/- 0.01 aF/rtHz respectively. Multi-hour room temperature
+runs, with one core of each of the three gap types, proved the stability of
+their long-term sensitivities of 0.234 +/- 0.005 aF/rtHz, 0.338 +/- 0.009
+aF/rtHz, and 0.435 +/- 0.010 aF/rtHz for the ungapped (40-hour duration) and
+the 65 um and 130 um (28-hour duration) cores respectively. At 0.1 mHz, a
+critical frequency for space gravitational wave detectors, the respective
+sensitivities are 0.25 +/- 0.02 aF/rtHz, 0.35 +/- 0.02 aF/rtHz, and 0.53 +/-
+0.07 aF/rtHz. Measurements with the ungapped transformer configuration for
+temperatures from 325 K to 349 K further validate the dependence of the noise
+model on the temperature and permeability. The performance of our RCB with an
+ungapped core matches the calculated performance value and shows an improvement
+in signal-to-noise of two or more compared with capacitance bridges developed
+for similar applications. A further factor of about two noise reduction is
+achieved by cooling to 120 K.",2306.08124v3
+2023-08-25,High-susceptibility nanoparticles for micro-inductor core materials,"According to the laws of magnetism, the shape of magnetically soft objects
+limits the effective susceptibility. For example, spherical soft magnets cannot
+display an effective susceptibility larger than 3. Although true for
+macroscopic multi-domain magnetic materials, we show that magnetic
+nanoparticles in a single-domain state do not suffer from this limitation. This
+is a consequence of the particle moment being forced to saturation by the
+predominance of exchange forces, and only allowed to rotate coherently in
+response to thermal and/or applied fields. We apply statistical mechanics to
+determine the static and dynamic susceptibility of single-domain particles as a
+function of size, temperature and material parameters. Our calculations reveal
+that spherical single-domain particles with large saturation magnetisation and
+small magneto-crystalline anisotropy, e.g. FeNi particles, can have very a
+large susceptibility of 200 or more. We further show that susceptibility and
+losses can be tuned by particle easy axis alignment with the applied field in
+case of uniaxial anisotropy, but not for particles with cubic anisotropy. Our
+model is validated experimentally by comparison with measurements on
+nanocomposites containing spherical 11$\pm$3 nm $\gamma$-Fe$_2$O$_3$ particles
+up to 45 vol% finely dispersed in a polymer matrix. In agreement with the
+calculations for this specific material, the measured susceptibility of the
+composites is up to 17 ($\gg$3) and depends linearly on the volume fraction of
+particles. Based on these results, we predict that nanocomposites of 30 vol% of
+superparamagnetic FeNi particles in an insulating non-magnetic matrix can have
+a sufficiently large susceptibility to be used as micro-inductor core materials
+in the MHz frequency range, while maintaining losses below state-of-the-art
+ferrites.",2308.13407v2
+2023-09-16,Temperature-Induced Hexagonal-Orthorhombic Phase Transition in Lutetium Ferrite Nanoparticles,"The X-ray diffraction, Raman and infrared spectroscopies and magnetic
+measurements were used to explore the correlated changes of the structure,
+lattice dynamics and magnetic properties of the LuFeO3 nanoparticles, which
+appear in dependence on their sintering temperature. We revealed a gradual
+substitution of the hexagonal phase by the orthorhombic phase in the
+nanoparticles, which sintering temperature increases from 700 C to 1100 C. The
+origin and stability of the hexagonal phase in the LuFeO3 nanoparticles is of
+the special interest, because the nanoparticle in the phase can be a
+room-temperature multiferroic with a weak ferromagnetic and pronounced
+structural and ferroelectric long-range ordering, while the antiferromagnetic
+and nonpolar orthorhombic phase is more stable in the bulk LuFeO3. To define
+the ranges of the hexagonal phase stability, we determine the bulk and
+interface energy densities of different phases from the comparison of the Gibbs
+model with experimental results. Using the Gibbs model parameters, we predict
+the influence of size effects and temperature on the structural and polar
+properties of the LuFeO3 nanoparticles. Analysis of the obtained results shows
+that the combination of the X-ray diffraction, Raman and infrared spectroscopy,
+magnetic measurements and theoretical modelling of structural and polar
+properties allows to establish the interplay between the phase composition,
+lattice dynamics and multiferroic properties of the LuFeO3 nanoparticles
+prepared in different conditions.",2309.09109v5
+2023-09-24,In-depth investigations of size and occupancies in cobalt ferrite nanoparticles by joint Rietveld refinements of X-ray and neutron powder diffraction data,"Powder X-ray diffraction (PXRD) and neutron powder diffraction (NPD) have
+been used to investigate the crystal structure of CoFe2O4 nanoparticles
+prepared via different hydrothermal synthesis routes, with particular attention
+given to accurately determining the spinel inversion degrees. The study is
+divided into four parts. In the first part, the investigations focus on the
+influence of using different diffraction pattern combinations (NPD, Cu-source
+PXRD and Co-source PXRD) for the structural modelling. It is found that
+combining PXRD data from a Co source with NPD data offers a robust structural
+model. The second part of the study evaluates the reproducibility of the
+employed multipattern Rietveld refinement procedure using different data sets
+collected on the same sample, as well as on equivalently prepared samples. The
+refinement procedure gives reproducible results and reveals that the synthesis
+method is likewise reproducible since only minor differences are noted between
+the samples. The third part focuses on the structural consequences of (i) the
+employed heating rate (achieved using three different hydrothermal reactor
+types) and (ii) changing the cobalt salt in the precursors [aqueous salt
+solutions of Co(CH3COOH)2, Co(NO3)2 and CoCl2] in the synthesis. It is found
+that increasing the heating rate causes a change in the crystal structure (unit
+cell and crystallite sizes) while the Co/Fe occupancy and magnetic parameters
+remain similar in all cases. Also, changing the type of cobalt salt does not
+alter the final crystal/magnetic structure of the CoFe2O4 nanoparticles. The
+last part of this study is a consideration of the chemicals and parameters used
+in the synthesis of the different samples.",2309.16037v1
+2023-11-06,Grain-level effects on in-situ deformation-induced phase transformations in a complex-phase steel using 3DXRD and EBSD,"A novel complex-phase steel alloy is conceived with a deliberately unstable
+austenite, $\gamma$, phase that enables the deformation-induced martensitic
+transformations (DIMT) to be explored at low levels of plastic strain. The DIMT
+was thus explored, in-situ and non-destructively, using both far-field
+Three-Dimensional X-Ray Diffraction (3DXRD) and Electron Back-Scatter
+Diffraction (EBSD). Substantial $\alpha'$ martensite formation was observed
+under 10% applied strain with EBSD, and many $\varepsilon$ grain formation
+events were captured with 3DXRD, indicative of the indirect transformation of
+martensite via the reaction $\gamma \rightarrow \varepsilon \rightarrow
+\alpha'$. Using $\varepsilon$ grain formation as a direct measurement of
+$\gamma$ grain stability, the influence of several microstructural properties,
+such as grain size, orientation and neighbourhood configuration, on $\gamma$
+stability have been identified. Larger $\gamma$ grains were found to be less
+stable than smaller grains. Any $\gamma$ grains oriented with {100} parallel to
+the loading direction preferentially transformed with lower stresses. Parent
+$\varepsilon$-forming $\gamma$ grains possessed a neighbourhood with increased
+ferritic/martensitic volume fraction. This finding shows, unambiguously, that
+$\alpha$/$\alpha'$ promotes $\varepsilon$ formation in neighbouring grains. The
+minimum strain work criterion model for $\varepsilon$ variant prediction was
+also evaluated, which worked well for most grains. However,
+$\varepsilon$-forming grains with a lower stress were less well predicted by
+the model, indicating crystal-level behaviour must be considered for accurate
+$\varepsilon$ formation. The findings from this work are considered key for the
+future design of alloys where the deformation response can be controlled by
+tailoring microstructure and local or macroscopic crystal orientations.",2311.03088v2