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2018-01-04
Tunable magnetic and transport properties of Mn3Ga thin films on Ta/Ru seedlayer
Hexagonal D019-type Mn3Z alloys that possess large anomalous and topological-like Hall effects have attracted much attention due to their great potential in the antiferromagnetic spintronic devices. Here, we report the preparation of Mn3Ga film in both tetragonal and hexagonal phases with a tuned Ta/Ru seed layer on th...
1801.01233v1
2018-01-10
Electronic band structure engineering in InAs/InSbAs and InSb/InSbAs superlattice heterostructures
We report a detailed ab initio study of two superlattice heterostructures, one component of which is a unit cell of CuPt ordered InSb_(0.5)As_(0.5). This alloy part of the heterostructures is a topological semimetal. The other component of each system is a semiconductor, zincblende-InSb, and wurtzite-InAs. Both heteros...
1801.03392v2
2017-12-02
On performance of nano-resonators produced by magnetron sputtering deposition
Magnetron sputtering is a perfect technique for processing nanomaterials for engineering and medical applications. A material can be processed with specific mechanical properties, microstructure, and surface texture by controlling the parameters of magnetron sputtering. Therefore, studies should be conducted on investi...
1801.06529v1
2018-01-25
Overdriven dislocation-precipitate interactions at elevated temperatures in aluminum
The two-dimensional dislocation dynamics approach has been recently used for analyzing plastic deformation in metals and alloys at elevated temperatures. The two-dimensional approach, however, only accounts for the dislocation climbing process, and it assumes that dislocation bypassing and shearing of precipitates are ...
1801.08623v1
2018-01-30
EMME: a formal tool for ECMAScript Memory Model Evaluation
Nearly all web-based interfaces are written in JavaScript. Given its prevalence, the support for high performance JavaScript code is crucial. The ECMA Technical Committee 39 (TC39) has recently extended the ECMAScript language (i.e., JavaScript) to support shared memory accesses between different threads. The extension...
1801.10140v2
2018-03-01
Characterisation of slip and twinning in high rate deformed zirconium with electron backscatter diffraction
Zirconium alloys are used in the nuclear industry as structural materials, and can be subject to high strain rate loading conditions during forming and in the case of a reactor accident. In this context, the relationship between strain rate dependent mechanical properties, crystallographic texture and deformation modes...
1803.00236v1
2018-03-07
Ultra-Fast Ferrimagnetic All Spin Logic Device
All spin logic device (ASLD) blazes an alternative path for realizing ultra-low power computing in the Post-Moore era. However, initial device structure relying on ferromagnetic input/output and spin transfer torque (STT) driven magnetization switching degrades its performance and even hinders its realization. In this ...
1803.02552v1
2018-03-08
Atomic motion in solids with dimpled potentials
Polymorphic solids of the same chemical composition can have different atomic structures; in each polymorph atoms vibrate around a local potential energy minimum (LPEM). If transformations to other structures have sufficiently high enthalpy barriers, then each polymorph is either stable or metastable; it is stationary ...
1803.03286v1
2018-03-09
Fundamental and Progress of Bi2Te3-based Thermoelectric Materials
Thermoelectric materials, enabling the directing conversion between heat and electricity, are one of the promising candidates for overcoming environmental pollution and the upcoming energy shortage caused by the over-consumption of fossil fuels. Bi2Te3-based alloys are the classical thermoelectric materials working nea...
1803.03386v1
2018-03-10
Statistical mechanics of high-density bond percolation
High-density (HD) percolation describes the percolation over specific $\kappa$ -clusters, which are the compact sets of sites each connected to $\kappa$ nearest filled sites at least. It takes place in the classical patterns of independently distributed sites or bonds in which the ordinary percolation transition also e...
1803.03785v2
2018-03-15
Low Temperature Ageing Behaviour of U-Nb $α''$ Phase Alloys
Ageing mechanisms of the U-5\,\%wtNb system have been investigated on samples exposed to temperatures of 150$\,^{\circ}$C for up to 5000\,hours. A variety of surface and bulk analytic techniques have been used to investigate phase, chemical and crystallographic changes. Characterisation of microstructural evolution was...
1803.05709v1
2018-03-19
High temperature magnetism and microstructure of semiconducting ferromagnetic alloy (GaSb)$_{1-x}$(MnSb)$_{x}$
We have studied the properties of relatively thick (about 120 nm) magnetic composite films grown by pulsed laser deposition method using (GaSb)$_{0.59}$(MnSb)$_{0.41}$ eutectic compound as a target for sputtering. For the studied films we have observed ferromagnetism and anomalous Hall effect above the room temperature...
1803.06769v1
2018-03-20
Ordered array of $ω$ particles in $β$-Ti matrix studied by small-angle X-ray scattering
Nanosized particles of $\omega$ phase in a $\beta$-Ti alloy were investigated by small-angle X-ray scattering using synchrotron radiation. We demonstrated that the particles are spontaneously weakly ordered in a three-dimensional cubic array along the $\langle 100\rangle$-directions in the $\beta$-Ti matrix. The small-...
1803.07403v1
2018-05-01
Al$_x$Ga$_{1-x}$As crystals with direct 2 eV band gaps from computational alchemy
We use alchemical first order derivatives for the rapid yet robust prediction of band structures. The power of the approach is demonstrated for the design challenge of finding Al$_x$Ga$_{1-x}$As semiconductor alloys with large direct band gap using computational alchemy within a genetic algorithm. Dozens of crystal pol...
1805.00299v3
2018-05-07
Highly efficient spin current generation by the spin Hall effect in Au$_{1-x}$Pt$_x$
We report very efficient spin current generation by the spin Hall effect in the alloy Au0.25Pt0.75, which, as determined by two different direct spin-orbit torque measurements, exhibits a giant internal spin Hall ratio of > 0.58 (anti-damping spin-orbit torque efficiency of ~ 0.35 in bilayers with Co), a relatively low...
1805.02329v3
2018-05-08
Spin-Hall and Anisotropic Magnetoresistance in Ferrimagnetic Co-Gd / Pt layers
We present the Co-Gd composition dependence of the spin-Hall magnetoresistance (SMR) and anisotropic magnetoresistance (AMR) for ferrimagnetic Co100-xGdx / Pt bilayers. With Gd concentration x, its magnetic moment increasingly competes with the Co moment in the net magnetization. We find a nearly compensated ferrimagne...
1805.02827v2
2018-05-09
Spatial Poisson processes for fatigue crack initiation
In this work we propose a stochastic model for estimating the occurrence of crack initiations on the surface of metallic specimens in fatigue problems that can be applied to a general class of geometries. The stochastic model is based on spatial Poisson processes with intensity function that combines stress-life (S-N) ...
1805.03433v2
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 ...
1805.04204v1
2018-05-23
Evidence of nanoscale Anderson localization induced by intrinsic compositional disorder in InGaN/GaN quantum wells by scanning tunneling luminescence spectroscopy
We present direct experimental evidences of Anderson localization induced by the intrinsic alloy compositional disorder of InGaN/GaN quantum wells. Our approach relies on the measurement of the luminescence spectrum under local injection of electrons from a scanning tunneling microscope tip into a near-surface single q...
1805.09030v1
2018-05-29
Gilbert damping in non-collinear magnetic system
The modification of the magnetization dissipation or Gilbert damping caused by an inhomogeneous magnetic structure and expressed in terms of a wave vector dependent tensor $\underline{\alpha}(\vec{q})$ is investigated by means of linear response theory. A corresponding expression for $\underline{\alpha}(\vec{q})$ in te...
1805.11468v1
2018-05-30
Does Stochastic Disorder Conform to Configurational Disorder?
In alloy thermodynamics, stochastically disordered state (SDS), where each lattice point is stochastically occupied by constituents according to given composition, is typically referred to investigating physical properties for homogeneously substitutional state: The so-called special quasirandom structure (SQS) of a si...
1805.12046v2
2018-06-04
Strong Resonances of Quasi 1D Structures at the Bi/InAs(100) Surface
Thin Bi films are interesting candidates for spintronic applications due to a large spin-orbit splitting that, combined with the loss of inversion symmetry at the surface, results in a band structure that is not spin-degenerate. In recent years, applications for topological insulators based on Bi and Bi alloys have as ...
1806.01031v2
2018-06-04
Current-induced domain wall motion in compensated ferrimagnet
Due to the difficulty in detecting and manipulating magnetic states of antiferromagnetic materials, studying their switching dynamics using electrical methods remains a challenging task. In this work, by employing heavy metal/rare earth-transition metal alloy bilayers, we experimentally studied current-induced domain w...
1806.01167v1
2018-06-05
Efficient technique for ab-initio calculation of magnetocrystalline anisotropy energy
Ab-initio calculation of magnetocrystalline anisotropy energy (MCAE) often requires a strict convergence criterion and a dense k-point mesh to sample the Brillouin zone, making its convergence problematic and time-consuming. The force theorem for MCAE states that MCAE can be calculated by the band energy difference bet...
1806.01536v2
2018-06-07
Terahertz Emission from Compensated Magnetic Heterostructures
Terahertz emission spectroscopy (TES) has recently played an important role in unveiling the spin dynamics at a terahertz (THz) frequency range. So far, ferromagnetic (FM)/nonmagnetic (NM) heterostructures have been intensively studied as THz sources. Compensated magnets such as a ferrimagnet (FIM) and antiferromagnet ...
1806.02517v1
2018-06-07
Diagonal flipping of a Rhombus as elementary act of a polymorphic transformation. Calculation of energy threshold for the transformation in metals
Diagonal flipping of a rhombus consisting of two triangles sharing a common edge with atoms (ions) in vertices of the triangles is considered as an elementary act of the polymorphic transformation in metals. The estimation of the energy threshold for the diagonal flipping has been carried out for various combination of...
1806.02601v1
2018-06-08
Parameter free quantitative analysis of atom probe data by correlation functions: Application to the precipitation in Al-Zn-Mg-Cu
Atom probe tomography enables precise quantification of the composition of second phase particles from their early stages, leading to improved understanding of the thermodynamic and kinetic mechanisms of phase formation and quantify structure-property relationships. Here we demonstrate how approaches developed for smal...
1806.03141v1
2018-06-11
Hadron-quark phase transition: the QCD phase diagram and stellar conversion
Different extensions of the Nambu-Jona-Lasinio model, known to satisfy expected QCD chiral symmetry aspects, are used to investigate a possible hadron-quark phase transition at zero temperature and to build the corresponding binodal sections. We have shown that the transition point is very sensitive to the model parame...
1806.04170v2
2018-06-12
Complex magnetism and non-Fermi liquid state in the vicinity of the quantum critical point in the CeCo$_{1-x}$Fe$_x$Ge$_3$ series
We report extensive studies on the CeCo$_{1-x}$Fe$_{x}$Ge$_3$ alloys, which show quantum critical point (QCP) due to damping the antiferromagnetic order in CeCoGe$_3$ down to 0 K by doping with the paramagnetic CeFeGe$_3$ compound. The presence of QCP is confirmed by detecting the non-Fermi liquid behavior (NFL) using ...
1806.04656v1
2018-06-13
Low magnetic damping of ferrimagnetic GdFeCo alloys
We investigate the Gilbert damping parameter for rare earth (RE)-transition metal (TM) ferrimagnets over a wide temperature range. Extracted from the field-driven magnetic domain-wall mobility, the Gilbert damping parameter was as low as 0.0072 and was almost constant across the angular momentum compensation temperatur...
1806.04881v1
2018-06-16
High Performance Computing in Medical Image Analysis HuSSaR
In our former works we have made serious efforts to improve the performance of medical image analysis methods with using ensemble-based systems. In this paper, we present a novel hardware-based solution for the efficient adoption of our complex, fusion-based approaches for real-time applications. Even though most of th...
1806.06171v1
2018-06-17
Influence of carrier lifetime on quantum criticality and superconducting Tc of (TMTSF)_2ClO_4
This work presents and analyzes electrical resistivity data on the organic superconductor (TMTSF)$_2$ClO$_4$ and their anion substituted alloys (TMTSF)$_2$(ClO$_4$)$_{1-x}$(ReO$_4$)$_x$ along the least conducting $c^\star$ axis. Nonmagnetic disorder introduced by finite size domains of anion ordering on non Fermi liqui...
1806.06395v1
2018-06-20
Magneto-optic Kerr effect in a spin-polarized zero-moment ferrimagnet
The magneto-optical Kerr effect (MOKE) is often assumed to be proportional to the magnetisation of a magnetically ordered metallic sample; in metallic ferrimagnets with chemically distinct sublattices, such as rare-earth transition-metal alloys, it depends on the difference between the sublattice contributions. Here we...
1806.07719v2
2018-06-23
Crack growth resistance in metallic alloys: the role of isotropic versus kinematic hardening
The sensitivity of crack growth resistance to the choice of isotropic or kinematic hardening is investigated. Monotonic mode I crack advance under small scale yielding conditions is modelled via a cohesive zone formulation endowed with a traction-separation law. R-curves are computed for materials that exhibit linear o...
1806.08986v1
2018-06-25
The stability and physical properties of the tetragonal phase of bulk CuMnAs antiferromagnet
The effect of Cu substitution on the stability of the CuMnAs tetragonal phase was studied both experimentally and by ab initio calculations. Polycrystalline samples with various compositions Cu$_{1+x}$Mn$_{1-x}$As $(x = 0 - 0.5)$ were synthetized. The tetragonal phase of CuMnAs is found to be stabilized by substituting...
1806.09459v1
2018-06-25
Mid-wave and Long-wave IR Linear Dichroism in a Hexagonal Perovskite Chalcogenide
Mid-wave infrared (IR) and long-wave IR spectral ranges are of growing interest in various applications such as thermal imaging, thermography-based remote sensing, and night vision. Materials widely used for IR photodetectors in this regime include cadmium mercury telluride alloys and nanostructures of compound semicon...
1806.09688v1
2018-06-27
Electronic properties of the ternary system YbPd$_2 $Ge$_{2-x}$
The data on the electronic and magnetic properties of the ternary ytterbium-based alloy YbPd$_2 $Ge$_{1.7}$ are presented and compared with those for YbPd$_2 $Ge$_{2}$ and YbPd$_2 $Ge compounds. YbPd$_2 $Ge$_{1.7}$ demonstrates a moderate heavy-fermion behavior with linear specific heat coefficient $\gamma \simeq $ 100...
1806.10323v1
2018-09-10
Quantification challenges for atom probe tomography of hydrogen and deuterium in Zircaloy-4
Analysis and understanding of the role of hydrogen in metals is a significant challenge for the future of materials science, and this is a clear objective of recent work in the atom probe tomography (APT) community. Isotopic marking by deuteration has often been proposed as the preferred route to enable quantification ...
1809.03556v2
2018-09-12
Detection of hydrogen by the extraordinary Hall effect in CoPd alloys
Effect of hydrogen adsorption on the extraordinary Hall phenomenon (EHE) in ferromagnetic CoPd films is studied as a function of composition, thickness, substrate and hydrogen concentration in atmosphere. Adsorption of hydrogen adds a positive term in the extraordinary Hall effect coefficient and modifies the perpendic...
1809.04515v1
2018-09-13
Linear complexions: Metastable phase formation and coexistence at dislocations
The unique three-phase coexistence of metastable B2-FeNi with stable L10-FeNi and L12-FeNi3 is discovered near edge dislocations in body-centered cubic Fe-Ni alloys using atomistic simulations. Stable nanoscale precipitate arrays, formed along the compression side of dislocation lines and defined as linear complexions,...
1809.05201v4
2018-09-17
Electric-Field Control of Magnetic Order: From FeRh to Topological Antiferromagnetic Spintronics
Using an electric field instead of an electric current (or a magnetic field) to tailor the electronic properties of magnetic materials is promising for realizing ultralow energy-consuming memory devices because of the suppression of Joule heating, especially when the devices are scaled to the nanoscale. In the review, ...
1809.06011v1
2018-08-25
Mid-infrared GeSn Electro-Absorption Optical Modulators on Silicon
Mid-infrared silicon photonics has recently emerged as a new technology for a wide range of applications such as optical communication, lidar, and bio-sensing. One key component enabling this technology is the mid-infrared optical modulator used for encoding optical signals. Here, we present a GeSn electro-absorption m...
1809.07150v1
2018-09-19
Rapid Electron Backscatter Diffraction Mapping: Painting by Numbers
Microstructure characterisation has been greatly enhanced through the use of electron backscatter diffraction (EBSD), where rich maps are generated through analysis of the crystal phase and orientation in the scanning electron microscope (SEM). Conventional EBSD analysis involves raster scanning of the electron beam an...
1809.07283v2
2018-09-24
On the segregation of Re at dislocations in the γ' phase of Ni-based single crystal superalloys
We report evidence of Re and Mo segregation (up to 2.6 at.% and 1 at.%) along with Cr and Co to the dislocations inside of {\gamma}' precipitates in a second generation Ni-based single crystal superalloy, after creep deformation at 750{\deg}C under an applied stress of 800 MPa. The observed segregation effects can be r...
1809.08776v1
2018-09-19
Thermal conductivity reduction by acoustic Mie resonance in nanoparticles
We evaluate the impact of acoustic Mie resonance in nanoparticles on the thermal conductivity of semiconductor and polymer composites. By appropriately choosing the bulk modulus and density, and selecting the size of the nanoparticle to align the Mie resonances with the dominant portion of the thermal conductivity spec...
1809.08913v1
2018-09-25
Theory of damping in magnetization dynamics, dispelling a myth and pointing a way forward
There is a widely-held belief amongst theoreticians that the Gilbert damping parameter {\alpha} in magnetization dynamics is infinite for a pure metal at T=0. The basic error leading to this belief is pointed out explicitly and the various methods of calculation used are viewed in a unified way based on the Lorentzian ...
1809.09429v1
2018-09-26
Strongly out-of-equilibrium columnar solidification during the Laser Powder-Bed Fusion additive manufacturing process
Laser-based additive manufacturing offers a promising route for 3D printing of metallic parts. We evidence experimentally a particular columnar solidification microstructure in a Laser Powder-Bed Fusion processed Inconel 718 nickel-based alloy, that we interpret using phase-field simulations and classical dendritic gro...
1809.09882v1
2018-09-26
Thermoelectric studies of Ir$_{1-x}$Rh$_{x}$Te$_{2}$ (0 $\leqslant x \leqslant $ 0.3)
We report thermoelectric properties of Ir$_{1-x}$Rh$_x$Te$_2$ ($0 \leqslant x \leqslant 0.3$) alloy series where superconductivity at low temperatures emerges as the high-temperature structural transition ($T_s$) is suppressed. The isovalent ionic substitution of Rh into Ir has different effects on physical properties ...
1809.10137v1
2018-09-27
Competing rhombohedral and monoclinic crystal structures in Mn$Pn_2Ch_4$ compounds: an {\em ab-initio} study
Based on the relativistic spin-polarized density functional theory calculations we investigate the crystal structure, electronic and magnetic properties of a family MnPn2Ch4 compounds, where pnictogen metal atoms (Pn) are Sb and Bi; chalcogens (Ch) are Se, Te. We show that in the series the compounds of this family wit...
1809.10343v1
2018-10-31
Complex Crystals from Size-disperse Spheres
Colloids are rarely perfectly uniform but follow a distribution of sizes, shapes, and charges. This dispersity can be inherent (static) or develop and change over time (dynamic). Despite a long history of research, the conditions under which non-uniform particles crystallize and which crystal forms is still not well un...
1811.00061v3
2018-11-06
Disordered skyrmion phase stabilized by magnetic frustration in a chiral magnet
Magnetic skyrmions are vortex-like topological spin textures often observed to form a triangular-lattice skyrmion crystal in structurally chiral magnets with Dzyaloshinskii-Moriya interaction. Recently $\beta$-Mn structure-type Co-Zn-Mn alloys were identified as a new class of chiral magnet to host such skyrmion crysta...
1811.02337v1
2018-11-06
The influence of complex thermal treatment on mechanical properties of amorphous materials
We study the effect of periodic, spatially uniform temperature variation on mechanical properties and structural relaxation of amorphous alloys using molecular dynamics simulations. The disordered material is modeled via a non-additive binary mixture, which is annealed from the liquid to the glassy state with various c...
1811.02365v1
2018-11-07
Effects of dopants on the glass forming ability in Al-based metallic alloy
The effect of dopants on the metallic glass forming ability is usually considered based on analysis of changes in the liquid structure or thermodynamics. What is missing in such considerations is an analysis of how a dopant changes the properties of the crystal phases which can form instead of the glass. In order to il...
1811.02985v3
2018-11-09
Multi-Cell Monte Carlo Method for Phase Prediction
We propose a Multi-Cell Monte Carlo algorithm, or (MC)^2, for predicting stable phases in chemically complex crystalline systems. Free atomic transfer among cells is achieved via the application of the lever rule, where an assigned molar ratio virtually controls the percentage of each cell in the overall simulation, ma...
1811.04092v1
2018-11-12
Exploration of the Microstructure Space in TiAlZrN Ultra-Hard Nanostructured Coatings
Ti$_{1-x-y}$Al$_{x}$Zr$_{y}$N cubic alloys within the 25-70\% Al composition range have high age-hardening capabilities due to metastable phase transition pathways at high temperatures. They are thus ideal candidates for ultra-hard nano-coating materials. There is growing evidence that this effect is associated with th...
1811.05017v1
2018-11-16
Broken symmetry driven topological semi-metal to gaped phase transitions in SrAgAs
We show the occurence of Dirac, Triple point, Weyl semimetal and topological insulating phase in a single ternary compound using specific symmetry preserving perturbations. Based on {\it first principle} calculations, \textbf{\textit{k.p}} model and symmetry analysis, we show that alloying induced precise symmetry brea...
1811.06685v2
2018-11-16
Precise Kohn-Sham total-energy calculations at reduced cost
The standard way to calculate the Kohn-Sham orbitals utilizes an approximation of the potential. The approximation consists in a projection of the potential into a finite subspace of basis functions. The orbitals, calculated with the projected potential, are used to evaluate the kinetic part of the total energy, but th...
1811.06788v1
2018-11-19
Carbon nanotube-copper fibers produced by electrospinning: electrical conductivity measurements
Recent advances in nanotechnology have provided new materials which have the potential to surpass copper and aluminum alloys in electrical conductivity, weight and ampacity [2-6]. Among these carbon nanotubes (CNTs) stand out due to their remarkable thermal and electrical conductivity and ampacity (103 times of copper)...
1811.07446v1
2018-11-19
A model for the evolution of highly reversible martensitic transformations
In this work we introduce a new system of partial differential equations as a simplified model for the evolution of reversible martensitic transformations under thermal cycling in low hysteresis alloys. The model is developed in the context of nonlinear continuum mechanics, where the developed theory is mostly static, ...
1811.07664v1
2018-11-20
Analysis of a moving mask approximation for martensitic transformations
In this work we introduce a moving mask approximation to describe the dynamics of austenite to martensite phase transitions at a continuum level. In this framework, we prove a new type of Hadamard jump condition, from which we deduce that the deformation gradient must be of the form $\mathsf{1} +\mathbf{a}\otimes \math...
1811.08247v1
2018-11-21
Bonding mechanisms in cold spray deposition of gas atomised and solution heat-treated Al 6061 powder by EBSD
The heat-treatment of a number of gas atomised aluminium alloys prior to cold spraying recently showed that the resultant microstructural modification was accompanied by an improvement in deposition; however, the relationship between the microstructural homogenisation occurring after recrystallisation and the increase ...
1811.08694v1
2018-11-21
Electron effective mass and electronic structure in nonstoichiometric a-IGZO films
The transport properties and optical transmittance and absorption spectra for the nostoichiometric amorphous Indium Gallium Zinc Oxide (a-IGZO) films with Gallium and Zinc deficiencies are investigated. The resistivity and carrier concentration variation with temperature both reveal that the films possess degenerate se...
1811.08766v2
2018-11-24
Mutual Influence of Different Hydrogen Concentration in α-Zirconium System with Vacancies
Hydrogen embrittlement in zirconium alloys is one of current challenges of nuclear reactor containment and can lead to a rapid decrease in mechanical properties of materials. Although many previous studies investigated the mechanism of hydrogen embrittlement at high hydrogen concentration, few studies concentrate on th...
1811.09856v1
2018-11-25
Temperature-Dependent Magnetization Reversal in Exchange Bias NiFe/IrMn/NiFe Structures
We demonstrate the magnetization reversal features in NiFe/IrMn/NiFe thin-film structures with 40% and 75% relative content of Ni in Permalloy in the temperature range from 80 K to 300 K. At the descending branches of the hysteresis loops, the magnetization reversal sequence of the two ferromagnetic layers is found to ...
1811.09963v1
2018-11-28
3D-Printed Chiral Metasurface as Dichroic Dual-Band Polarization Converter
We propose a novel design of a true 3D chiral metasurface behaving as a spatial polarization converter with asymmetric transmission. The metasurface is made of a lattice of metallic sesquialteral (one and a half pitch) helical particles. Each particle contains six rectangular bars arranged in a series one above the ano...
1811.11747v1
2019-11-01
Tuning interfacial Dzyaloshinskii-Moriya interactions in thin amorphous ferrimagnetic alloys
Skyrmions can be stabilized in magnetic systems with broken inversion symmetry and chiral interactions, such as Dzyaloshinskii-Moriya interactions (DMI). Further, compensation of magnetic moments in ferrimagnetic materials can significantly reduce magnetic dipolar interactions, which tend to favor large skyrmions. Tuni...
1911.00607v1
2019-11-04
Interatomic Potential in a Simple Dense Neural Network Representation
Simulations at the atomic scale provide a direct and effective way to understand the mechanical properties of materials. In the regime of classical mechanics, simulations for the thermodynamic properties of metals and alloys can be done by either solving the equations of motion or performing Monte Carlo sampling. The k...
1911.01365v1
2019-11-06
Ab initio typical medium theory of substitutional disorder
By merging single-site typical medium theory with density functional theory we introduce a self-consistent framework for electronic structure calculations of materials with substitutional disorder which takes into account Anderson localization. The scheme and details of the implementation are presented and applied to t...
1911.02393v2
2019-11-07
Green luminescence and calculated optical properties of Cu ions in ZnO
There are two characteristic optical transitions associated with Cu ions in ZnO, the 0.72 eV infrared and the 2.86 eV structured green luminescence (SGL). While the former is unambiguously related with the d(Cu2+) intra-shell transition, there is no generally accepted mechanism of the SGL. Besides the original model of...
1911.02826v1
2019-11-13
Effect of the polar distortion on the thermoelectric properties of GeTe
First principle calculations are performed to investigate the effect of polar order strength on the thermoelectric (TE) properties of GeTe alloy in its rhombohedral structure. The variation in the polarization state using various ferroelectric distortions {\lambda} ({\lambda}=0,0.5,1.0,1.25,1.5) allows to change the th...
1911.05301v2
2019-11-13
Strain and voltage control of magnetic and electric properties of FeRh films
FeRh based alloys may display an uncommon transition from a ferromagnetic to an antiferromagnetic state upon cooling. The transition takes place roughly above room temperature and it can be sensitively modulated by composition and external parameters, including pressure and strain. Consequently, thin films of FeRh have...
1911.05334v1
2019-11-19
Stochastic estimations of a total number of classes for the clusterings with too enormous samples to be accommodate into a clustering engine
We considered the problem how to handle the exploding number of possibilities to be sorted into irreducible classes by using a clustering tool when its input capacity cannot accommodate the total number of the possibility. Concrete situations are explained taking examples of atomic substitutions in the supercell modeli...
1911.08071v2
2019-11-27
Coupled Sublattice Melting and Charge-Order Transition in Two Dimensions
Two-dimensional melting is one of the most fascinating and poorly understood phase transitions in nature. Theoretical investigations often point to a two-step melting scenario involving unbinding of topological defects at two distinct temperatures. Here we report on a novel melting transition of a charge-ordered K-Sn a...
1911.11921v1
2019-11-27
Computational screening of magnetocaloric alloys
An exciting development over the past few decades has been the use of high-throughput computational screening as a means of identifying promising candidate materials for a variety of structural or functional properties. Experimentally, it is often found that the highest-performing materials contain substantial atomic s...
1911.12218v3
2019-11-29
Galvanic Replacement Reaction to prepare nanoporous Aluminum for UV plasmonics
Plasmonics applications have been extending into the ultraviolet region of the electromagnetic spectrum. Unfortunately the commonly used noble metals have intrinsic optical properties that limit their use above 350 nm. Aluminum is probably the most suitable material for UV plasmonics and in this work we show that nanop...
1911.13198v1
2020-01-07
Electrical transport properties of bulk tetragonal CuMnAs
Temperature-dependent resistivity and magnetoresistance are measured in bulk tetragonal phase of antiferromagnetic CuMnAs and the latter is found to be anisotropic both due to structure and magnetic order. We compare these findings to model calculations with chemical disorder and finite-temperature phenomena included. ...
2001.01947v3
2020-01-08
Enhanced attraction between particles in a bidisperse mixture with random pair-wise interactions
Motivated by growing interests in multicomponent metallic alloys and complex fluids, we study a complex mixture with bidispersity in size and polydispersity in energy. The energy polydispersity in the system is introduced by considering random pair-wise interactions between the particles. Extensive molecular dynamics s...
2001.02730v1
2020-01-15
Effective interaction model for coupled magnetism and phase stability in bcc Fe-Co systems
We present an ab-initio-based effective interaction model (EIM) for the study of magnetism, thermodynamics, and their interplay in body-centered cubic Fe-Co alloys, with Co content from 0 to 70%. The model includes explicitly both spin and chemical variables. For the former, a Heisenberg formalism is adopted. But, the ...
2001.05342v1
2020-01-15
Quantum critical point in the itinerant ferromagnet Ni$_{1-x}$Rh$_x$
We report a chemical substitution-induced ferromagnetic quantum critical point in polycrystalline Ni$_{1-x}$Rh$_x$ alloys. Through magnetization and muon spin relaxation measurements, we show that the ferromagnetic ordering temperature is suppressed continuously to zero at $x_{crit} = 0.375$ while the magnetic volume f...
2001.05533v1
2020-01-21
Single photon emission from droplet epitaxial quantum dots in the standard telecom window around a wavelength of 1.55 $μ$m
We study the luminescence dynamics of telecom wavelength InAs quantum dots grown on InP(111)A by droplet epitaxy. The use of the ternary alloy InAlGaAs as a barrier material leads to photon emission in the 1.55 $\mu$m telecom C-band. The luminescence decay is well described in terms of the theoretical interband transit...
2001.07329v1
2020-01-29
Morphological analysis of 3d atom probe data using Minkowski functionals
We present a morphological analysis of atom probe data of nanoscale microstructural features, using methods developed by the astrophysics community to describe the shape of superclusters of galaxies. We describe second-phase regions using Minkowski functionals, representing the regions' volume, surface area, mean curva...
2001.10762v1
2020-01-29
An atomistic perspective of martensite twinning in Iron
The martensitic transformation is one of the most important phenomena in metals science due to its essential contribution to the strength of steels and most engineering alloys. Yet the basic, atomistic mechanisms leading to martensite nucleation and twin morphology are not yet known. A detailed picture in this regard i...
2001.11053v1
2020-01-30
Extreme Fermi surface smearing in a maximally disordered concentrated solid solution
We show that the Fermi surface can survive the presence of extreme compositional disorder in the equiatomic alloy Ni$_{0.25}$Fe$_{0.25}$Co$_{0.25}$Cr$_{0.25}$. Our high-resolution Compton scattering experiments reveal a Fermi surface which is smeared across a significant fraction of the Brillouin zone (up to 40\% of $\...
2001.11416v1
2020-01-30
Disorder Dependence of Interface Spin Memory Loss
The discontinuity of a spin-current through an interface caused by spin-orbit coupling is characterized by the spin memory loss (SML) parameter {\delta}. We use first-principles scattering theory and a recently developed local current scheme to study the SML for Au|Pt, Au|Pd, Py|Pt and Co|Pt interfaces. We find a minim...
2001.11520v1
2021-07-02
Calculations of Real-System Nanoparticles Using Universal Neural Network Potential PFP
It is essential to explore the stability and activity of real-system nanoparticles theoretically. While applications of theoretical methods for this purpose can be found in literature, the expensive computational costs of conventional theoretical methods hinder their massive applications to practical materials design. ...
2107.00963v1
2021-07-11
Sampling Lattices in Semi-Grand Canonical Ensemble with Autoregressive Machine Learning
Calculating thermodynamic potentials and observables efficiently and accurately is key for the application of statistical mechanics simulations to materials science. However, naive Monte Carlo approaches, on which such calculations are often dependent, struggle to scale to complex materials in many state-of-the-art dis...
2107.05109v2
2021-07-12
Large anomalous Nernst effect in non-crystalline Gd-Fe ferrimagnetic alloy films for flexible thermoelectric applications
The anomalous Nernst effect (ANE), a heat-charge conversion mechanism based on a magnetic metal, has been extensively studied for application in thin thermoelectric devices. The low magnetization and fabrication at room temperature are important for flexible ANE thermoelectric devices on plastic substrates. Therefore, ...
2107.05215v2
2021-07-16
Discovery and implications of hidden atomic-scale structure in a metallic meteorite
Iron and its alloys have made modern civilisation possible, with metallic meteorites providing one of the human's earliest sources of usable iron as well as providing a window into our solar system's billion-year history. Here highest-resolution tools reveal the existence of a previously hidden FeNi nanophase within th...
2107.07909v1
2021-07-27
Dislocation assisted phase separation: a phase field study
Defects play a key role in deciding the mechanisms and kinetics of phase transformations. In this paper, we show how dislocations influence phase separation in alloys with miscibility gap. Specifically, depending on the ratio of pipe mobility to bulk mobility, it is seen that even in a system with nominal compositions ...
2107.12703v1
2021-07-28
Isotopic effect of proton conductivity in barium-zirconates for various hydrogen-containing atmospheres
Among various perovskite proton conducting oxides, Y-doped BaZrO3 perovskite is a promising material for electrochemical hydrogen devices due to the good chemical stability and higher proton conductivity at higher operating temperatures like 500-800 {\deg}C. For the practical application of the functional BaZrO3 proton...
2107.13604v1
2017-04-11
Low temperature transport properties of pyrolytic graphite sheet
We have made thermal and electrical transport measurements of uncompressed pyrolytic graphite sheet (uPGS), a mass-produced thin graphite sheet with various thicknesses between 10 and 100 {\mu}m, at temperatures between 2 and 300 K. Compared to exfoliated graphite sheets like Grafoil, uPGS has much higher conductivitie...
1704.03204v2
2017-04-12
Ultra-fast magnetization manipulation using single femtosecond light and hot-electrons pulse
Current induced magnetization manipulation is a key issue for spintronic application. Therefore, deterministic switching of the magnetization at the picoseconds timescale with a single electronic pulse represents a major step towards the future developments of ultrafast spintronic. Here, we have studied the ultrafast m...
1704.03749v1
2017-04-13
Switching of magnetic ground states across the UIr1-xRhxGe alloy system
We investigated the evolution of magnetism in the UIr1-xRhxGe system by the systematic study of high-quality single crystals. Lattice parameters of both parent compounds are very similar resulting in almost identical nearest interatomic uranium distance close to the Hill limit. We established the x-T phase diagram of t...
1704.04013v1
2017-04-13
almaBTE: a solver of the space-time dependent Boltzmann transport equation for phonons in structured materials
almaBTE is a software package that solves the space- and time-dependent Boltzmann transport equation for phonons, using only ab-initio calculated quantities as inputs. The program can predictively tackle phonon transport in bulk crystals and alloys, thin films, superlattices, and multiscale structures with size feature...
1704.04142v1
2017-04-21
Optically pumped GeSn micro-disks with 16 % Sn lasing at 3.1 um up to 180K
Recent demonstrations of optically pumped lasers based on GeSn alloys put forward the prospect of efficient laser sources monolithically integrated on a Si photonic platform. For instance, GeSn layers with 12.5% of Sn were reported to lase at 2.5 um wavelength up to 130 K. In this work, we report a longer emitted wavel...
1704.06436v1
2017-04-28
Retrieving the quantitative chemical information at nanoscale from SEM EDX measurements by Machine Learning
The quantitative composition of metal alloy nanowires on InSb(001) semiconductor surface and gold nanostructures on germanium surface is determined by blind source separation (BSS) machine learning (ML) method using non negative matrix factorization (NMF) from energy dispersive X-ray spectroscopy (EDX) spectrum image m...
1705.00081v1
2017-05-01
Large Thermoelectric Power Factor at Low Temperatures in One-Dimensional Telluride Ta4SiTe4
We report the discovery of a very large thermoelectric power over -400 microV K-1 in the whisker crystals of a one-dimensional telluride Ta4SiTe4, while maintaining a low electrical resistivity of rho = 2 mohm cm, yielding a very large power factor of P = 80 microW cm-1 K-2 at an optimum temperature of 130 K. This temp...
1705.00404v1
2017-05-02
A regression-based feature selection study of the Curie temperature of transition-metal rare-earth compounds: prediction and understanding
The Curie temperature ($T_C$) of binary alloy compounds consisting of 3$d$ transition-metal and 4$f$ rare-earth elements is analyzed by a machine learning technique. We first demonstrate that nonlinear regression can accurately reproduce $T_C$ of the compounds. The prediction accuracy for $T_C$ is maximized when five t...
1705.00978v2
2017-05-02
Machine learning reveals orbital interaction in crystalline materials
We propose a novel representation of crystalline materials named orbital-field matrix (OFM) based on the distribution of valence shell electrons. We demonstrate that this new representation can be highly useful in mining material data. Our experiment shows that the formation energies of crystalline materials, the atomi...
1705.01043v2
2017-05-11
Predicted novel insulating electride compound between alkali metals lithium and sodium under high pressure
The application of high pressure can fundamentally modify the crystalline and electronic structures of elements as well as their chemical reactivity, which could lead to the formation of novel materials. Here, we explore the reactivity of lithium with sodium under high pressure, using a swarm structure searching techni...
1705.04213v1