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2003-05-20
Very high upper critical fields in MgB2 produced by selective tuning of impurity scattering
We report a significant enhancement of the upper critical field $H_{c2}$ of different $MgB_2$ samples alloyed with nonmagnetic impurities. By studying films and bulk polycrystals with different resistivities $\rho$, we show a clear trend of $H_{c2}$ increase as $\rho$ increases. One particular high resistivity film had...
0305474v2
2004-02-19
Monte Carlo Study of the Precipitation Kinetics of Al3zr in Al-Zr
Zr precipitates in Al to form the phase Al3Zr. For a low supersaturation in Zr of the fcc solid solution, it has been observed that during the precipitation first steps the Al3Zr precipitates have the metastable L12 structure and that they transform themselves to the stable DO23 structure for long enough annealing time...
0402505v2
2006-10-03
Spin-Diffusion Lengths in Metals and Alloys, and Spin-Flipping at Metal/Metal Interfaces: an Experimentalist's Critical Review
In magnetoresistive (MR) studies of magnetic multilayers composed of combinations of ferromagnetic (F) and non-magnetic (N) metals, the magnetic moment (or related 'spin') of each conduction electron plays a crucial role, supplementary to that of its charge. While initial analyses of MR in such multilayers assumed that...
0610085v2
2008-04-16
Surface States of the Topological Insulator Bi_{1-x}Sb_x
We study the electronic surface states of the semiconducting alloy BiSb. Using a phenomenological tight binding model we show that the Fermi surface of the 111 surface states encloses an odd number of time reversal invariant momenta (TRIM) in the surface Brillouin zone confirming that the alloy is a strong topological ...
0804.2664v1
2010-10-25
Calculation of angle-resolved photo emission spectra within the one-step model of photo emission - recent developments
Various technical developments enlarged the potential of angle-resolved photo emission (ARPES) tremendously during the last one or two decades. In particular improved momentum and energy resolution as well as the use of photon energies from few eV up to several keV makes ARPES a rather unique tool to investigate the el...
1010.5086v1
2012-01-25
Homogenous and heterogeneous magnetism in (Zn,Co)O
A series of (ZnO)m(CoO)n digital alloys and superlattices grown by atomic layer deposition has been investigated by a range of experimental methods. The data provide evidences that the Co interdiffusion in the digital alloy structures is sufficient to produce truly random Zn1-xCoxO mixed crystals with x up to 40%. Conv...
1201.5268v1
2012-05-03
Structural relationships among monoclinic and hexagonal phases and transition structures in Mg-Zn-Y alloys
Isothermal ageing of plastically deformed Mg-Zn-Y alloys resulted in precipitation along {10-12} twin boundaries. The bulky precipitates formed had structures similar to those recently reported for the rod-like \beta' precipitates, but afforded a more detailed study by high resolution TEM due to their larger size. The ...
1205.0625v1
2012-06-03
Fe-C and Fe-H systems at pressures of the Earth's inner core
The solid inner core of the Earth is predominantly composed of iron alloyed with several percent Ni and some lighter elements, Si, S, O, H, and C being the prime candidates. There have been a growing number of papers investigating C and H as possible light elements in the core, but the results are contradictory. Here, ...
1206.0467v1
2012-10-10
A topological crystalline insulator (TCI) phase via topological phase transition and crystalline mirror symmetry
A Z2 topological insulator protected by time-reversal symmetry is realized via spin-orbit interaction driven band inversion. For example, the topological phase in the Bi-Sb system is due to an odd number of band inversions. A related spin-orbit system, the (Pb/Sn)Te class, has been known to contain an even number of in...
1210.2917v1
2013-03-12
Valence Fluctuation in CeMo2Si2C
We report on the valence fluctuation of Ce in CeMo$_{2}$Si$_{2}$C as studied by means of magnetic susceptibility $\chi(T)$, specific heat $C(T)$, electrical resistivity $\rho(T)$ and x-ray absorption spectroscopy. Powder x-ray diffraction revealed that CeMo$_{2}$Si$_{2}$C crystallizes in CeCr$_{2}$Si$_{2}$C-type layere...
1303.2801v1
2014-03-19
Dirac mass generation from crystal symmetry breaking on the surfaces of topological crystalline insulators
The tunability of topological surface states (SS) and controllable opening of the Dirac gap are of fundamental and practical interest in the field of topological materials. In topological crystalline insulators (TCIs), a spontaneously generated Dirac gap was recently observed, which was ascribed to broken cubic crystal...
1403.4906v2
2014-04-11
Fermi Surface Properties, Metamgnetic Transition and Quantum Phase Transition of CeRu$_2$Si$_2$ and Its Alloys Probed by the dHvA Effect--Fermi Surface Studies on the Itinerant and Localized Dichotomy of $f$ Electron Nature
This article describes the Fermi surface properties of CeRu$_2$Si$_2$ and its alloy systems CeRu$_2$(Si$_x$Ge$_{1-x}$)$_2$ and Ce$_x$La$_{1-x}$Ru$_2$Si$_2$ studied by the de Haas - van Alphen (dHvA) effect. We pay particular attention to how the Fermi surface properties and the f electron state change with magnetic pro...
1404.2991v1
2014-08-14
Review on magnetic and related properties of RTX compounds
RTX (R=rare earths, T= 3d/4d/5d, transition metals such as Sc, Ti, Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt, Au, and X=p-block elements such as Al, Ga, In, Si, Ge, Sn, As, Sb, Bi) series is a huge family of intermetallics compounds. These compounds crystallize in different crystal structures depending on the cons...
1408.3238v1
2015-02-20
Magnetic properties of (Fe$_{1-x}$Co$_x$)$_2$B alloys and the effect of doping by 5$d$ elements
We have explored, computationally and experimentally, the magnetic properties of \fecob{} alloys. Calculations provide a good agreement with experiment in terms of the saturation magnetization and the magnetocrystalline anisotropy energy with some difficulty in describing Co$_2$B, for which it is found that both full p...
1502.05916v3
2015-01-27
Thermodynamic model of solute site preferences in ordered alloys
A thermodynamic model based on the law of mass action is used to calculate concentrations of elementary point defects and to determine site preferences of solute atoms in ordered alloys. Combinations of lattice vacancies, antisite atoms and host interstitials that form equilibrium defects are enumerated for the CsCl (B...
1503.08068v1
2015-06-30
Materials with low DC magnetic susceptibility for sensitive magnetic measurements
Materials with very low DC magnetic susceptibility have many scientific applications. To our knowledge however, relatively little research has been conducted with the goal to produce a totally nonmagnetic material. This phrase in our case means after spatially averaging over macroscopic volumes, it possesses an average...
1506.09199v1
2016-01-29
Applicability of DFT + U to U metal and U-Zr alloy
In the Letter [J. Nucl. Mater. 444, 356 (2014)] and Comment [Phys Rev B 90, 157101 (2014)], Soderlind et al. argue that 1) DFT based on GGA already models U metal and U-Zr alloy accurately, and 2) DFT + U models them worse than DFT according to results they calculate or select from our recent study [Phys. Rev. B 88, 23...
1601.07959v1
2016-05-11
Experimental studies of crystal nucleation: metals and colloids
Crystallization is one of the most important phase transformations of first order. In the case of metals and alloys, the liquid phase is the parent phase of materials production. The conditions of the crystallization process control the as-solidified material in its chemical and physical properties. Nucleation initiate...
1605.03511v2
2016-10-26
Glass transitions, semiconductor-metal (SC-M) transitions and fragilities in Ge-V-Te (V=As, or Sb) liquid alloys: the difference one element can make
Glass transition temperatures (Tg) and liquid fragilities are measured along a line of constant Ge content in the system Ge-As-Te, and contrasted with the lack of glass-forming ability in the twin system Ge-Sb-Te at the same Ge content. The one composition established as free of crystal contamination in the latter syst...
1610.08164v2
2017-03-09
Material developments and domain wall based nanosecond-scale switching process in perpendicularly magnetized STT-MRAM cells
We investigate the Gilbert damping and the magnetization switching of perpendicularly magnetized FeCoB-based free layers embedded in tunnel junctions adequate for spin-torque operated memories. We study the influence of the boron content in MgO / FeCoB /Ta systems alloys on their Gilbert damping after crystallization a...
1703.03198v3
2017-09-26
Defect Role in the Carrier Tunable Topological Insulator (Bi$_{1-x}$Sb$_x$)$_2$Te$_3$ Thin Films
Alloys of Bi$_2$Te$_3$ and Sb$_2$Te$_3$ ((Bi$_{1-x}$Sb$_x$)$_2$Te$_3$) have played an essential role in the exploration of topological surface states, allowing us to study phenomena that would otherwise be obscured by bulk contributions to conductivity. Thin films of these alloys have been particularly important for tu...
1709.09133v1
2018-01-11
Ferromagnetic Quantum Critical Point in CePd$_2$P$_2$ with Pd $\rightarrow$ Ni Substitution
An investigation of the structural, thermodynamic, and electronic transport properties of the isoelectronic chemical substitution series Ce(Pd$_{1-x}$Ni$_x$)$_2$P$_2$ is reported, where a possible ferromagnetic quantum critical point is uncovered in the temperature - concentration ($T-x$) phase diagram. This behavior r...
1801.04000v3
2018-05-07
Diffusion and Phase Evolution in Multicomponent Multi-Phase Alloys
Diffusion in ternary, multiphase systems was studied theoretically and experimentally in Ni-Cr-Al system at 1200C. The samples were prepared by the multiple method. It has been shown that the method allows obtaining good quality, planar, reproducible and oxide-free diffusion couples. For the first time the concentratio...
1805.02388v1
2018-05-21
Towards Ultra Low Cobalt Cathodes: A High Fidelity Computational Phase Search of Layered Li-Ni-Mn-Co Oxides
Layered Li(Ni,Mn,Co,)O$_2$ (NMC) presents an intriguing ternary alloy design space for optimization as a cathode material in Li-ion batteries. Recently, the high cost and resource limitations of Co have added a new design constraint and high Ni-containing NMC alloys have gained enormous attention despite possible perfo...
1805.08171v2
2019-11-08
Room Temperature Spin to Charge Conversion in Amorphous Topological Insulating Gd-Alloyed BixSe1-x/CoFeB Bilayers
Disordered topological insulator (TI) films have gained intense interest by benefiting from both the TIs exotic transport properties and the advantage of mass production by sputtering. Here, we report on the clear evidence of spin-charge conversion (SCC) in amorphous Gd-alloyed BixSe1-x (BSG)/CoFeB bilayers fabricated ...
1911.03323v12
2019-11-22
Role of Element-Specific Damping on the Ultrafast, Helicity-Independent All-Optical Switching Dynamics in Amorphous (Gd,Tb)Co Thin Films
Ultrafast control of the magnetization in ps timescales by fs laser pulses offers an attractive avenue for applications such as fast magnetic devices for logic and memory. However, ultrafast helicity-independent all-optical switching (HI-AOS) of the magnetization has thus far only been observed in Gd-based, ferrimagnet...
1911.09803v3
2020-01-15
Polymorphism and superconductivity in the V-Nb-Mo-Al-Ga high-entropy alloys
High-entropy alloys (HEAs) are at the focus of current research for their diverse properties, including superconductivity and structural polymorphism. However, the polymorphic transition has been observed only in nonsuperconducting HEAs and mostly under high pressure. Here we report the discovery of superconductivity a...
2001.05193v1
2021-07-16
Intra-unitcell cluster-cluster magnetic compensation and large exchange bias in cubic alloys
Composite quantum materials are the ideal examples of multifunctional systems which simultaneously host more than one novel quantum phenomenon in physics. Here, we present a combined theoretical and experimental study to demonstrate the presence of an extremely large exchange bias in the range 0.8 T - 2.7 T and a fully...
2107.07742v1
2021-07-16
A growth diagram for chemical beam epitaxy of GaP$_{1-x}$N$_{x}$ alloys on nominally $(001)$-oriented GaP-on-Si substrates
The dilute-nitride ternary compound GaP$_{1-x}$N$_{x}$ is highly attractive to monolithically integrate pseudomorphic red light-emitting devices and photovoltaic cells with the standard Si technology because it is lattice matched to Si with a direct band gap of $\approx1.96$ eV for $x=0.021$. Here, we report on the che...
2107.07848v2
2017-04-18
Localization landscape theory of disorder in semiconductors II: Urbach tails of disordered quantum well layers
Urbach tails in semiconductors are often associated to effects of compositional disorder. The Urbach tail observed in InGaN alloy quantum wells of solar cells and LEDs by biased photocurrent spectroscopy is shown to be characteristic of the ternary alloy disorder. The broadening of the absorption edge observed for quan...
1704.05524v1
2017-05-17
InGaN Metal-IN Solar Cell: optimized efficiency and fabrication tolerance
Choosing the Indium Gallium Nitride (InGaN) ternary alloy for thin films solar cells might yield high benefits concerning efficiency and reliability, because its bandgap can be tuned through the Indium composition and radiations have little destructive effect on it. It may also reveal challenges because good quality p-...
1705.08256v1
2018-07-05
Mineralogy, structure and habitability of carbon-enriched rocky exoplanets: A laboratory approach
Carbon-enriched rocky exoplanets have been proposed around dwarf stars as well as around binary stars, white dwarfs and pulsars. However, the mineralogical make up of such planets is poorly constrained. We performed high-pressure high-temperature laboratory experiments ($P$ = 1$-$2 GPa, $T$ = 1523$-$1823 K) on carbon-e...
1807.02064v2
2018-07-27
Magnetocrystalline anisotropy of Fe5PB2 and its alloys with Co and 5d elements: a combined first-principles and experimental study
The Fe$_5$PB$_2$ compound offers tunable magnetic properties via the possibility of various combinations of substitutions on the Fe and P-sites. Here, we present a combined computational and experimental study of the magnetic properties of (Fe$_{1-x}$Co$_{x}$)$_5$PB$_2$. Computationally, we are able to explore the full...
1807.10649v3
2014-06-02
Compositional dependence of the direct and indirect band gaps in $\text{Ge}_{1-y}\text{Sn}_{y}$ alloys from room temperature photoluminescence
The compositional dependence of the lowest direct and indirect band gaps in $\text{Ge}_{1-y}\text{Sn}_{y}$ has been determined from room-temperature photoluminescence measurements. This technique is particularly attractive for a comparison of the two transitions because distinct features in the spectra can be associate...
1406.0448v1
2018-12-01
Extrinsic n-type semiconductor transition in ZrSe2 with the metallic character through hafnium substitution
Two dimensional layered materials exhibit versatile electronic properties in their different phases. The intrinsic electronic properties of these materials can be modulated through doping or intercalation. In this study, we investigated the electronic properties of Hf doped ZrSe2 single crystals using angle-resolved ph...
1812.00157v2
2018-11-25
Accelerating Photovoltaic Materials Development via High-Throughput Experiments and Machine-Learning-Assisted Diagnosis
Accelerating the experimental cycle for new materials development is vital for addressing the grand energy challenges of the 21st century. We fabricate and characterize 75 unique halide perovskite-inspired solution-based thin-film materials within a two-month period, with 87% exhibiting band gaps between 1.2 eV and 2.4...
1812.01025v1
2019-02-03
On the effect of Re addition on microstructural evolution of a CoNi-based superalloy
In this study, the effect of rhenium (Re) addition on microstructural evolution of a new low-density Co-Ni-Al-Mo-Nb based superalloy is presented. Addition of Re significantly influences the {\gamma}' precipitate morphology, the {\gamma}/{\gamma}' lattice misfit and the {\gamma}/{\gamma}' microstructural stability duri...
1902.00857v1
2019-02-15
Gutzwiller projection for exclusion of holes: Application to strongly correlated Ionic Hubbard Model and Binary Alloys
We consider strongly correlated limit of variants of the Hubbard model (HM) in which on parts of the system it is energetically favourable to project out doublons from the low energy Hilbert space while on other sites of the system it is favourable to project out holes while still allowing for doublons. As an effect th...
1902.05920v2
2020-04-09
Domain formation in the deposition of thin films of two-component mixtures
We perform a kinetic Monte Carlo simulation study of a model of thin film deposition of a two-component mixture in which the activation energy for diffusion of an adatom is additive over its nearest neighbors and in which the interactions between adatoms of the same species are stronger than those between adatoms of di...
2004.04853v2
2020-05-12
Defect filtering for thermal expansion induced dislocations in III-V lasers on silicon
Epitaxially integrated III-V semiconductor lasers for silicon photonics have the potential to dramatically transform information networks, but currently, dislocations limit performance and reliability even in defect tolerant InAs quantum dot (QD) based lasers. Despite being below critical thickness, QD layers in these ...
2005.06066v3
2020-05-21
Repairing and Mechanising the JavaScript Relaxed Memory Model
Modern JavaScript includes the SharedArrayBuffer feature, which provides access to true shared memory concurrency. SharedArrayBuffers are simple linear buffers of bytes, and the JavaScript specification defines an axiomatic relaxed memory model to describe their behaviour. While this model is heavily based on the C/C++...
2005.10554v2
2021-03-04
Crater shape as a possible record of the impact environment of metallic bodies: Effects of temperature, impact velocity and impactor density
Metallic bodies that were the cores of differentiated bodies are sources of iron meteorites and are considered to have formed early in the terrestrial planet region before migrating to the main asteroid belt. Surface temperatures and mutual collision velocities differ between the terrestrial planet region and the main ...
2103.03128v2
2022-02-09
Potential Tribological and Antibacterial Benefits of Pulsed Laser Deposited Zirconia Thin Film on Ti6Al4V Bio-alloy
Demand for artificial body implants has been on the rise over the years. However, wear and bacterial infection are identified as two major reasons that can lead to inflammation and implant failure. In this communication, the advantages of pulsed laser deposited zirconia thin film on Ti6Al4V bio-alloy at room temperatur...
2202.04290v1
2016-03-01
Magnetic properties of Fe$_5$SiB$_2$ and its alloys with P, S, and Co
Fe$_5$SiB$_2$ has been synthesized and magnetic measurements have been carried out, revealing that M$_{\text{sat}}$ = 0.92 MA/m at T = 300 K. The M vs T curve shows a broad peak around T = 160 K. The anisotropy constant, K$_1$, estimated at T = 300 K, is 0.25 MJ/m$^3$. Theoretical analysis of Fe$_5$SiB$_2$ system has b...
1603.00253v1
2017-06-21
Electronic bandstructure and optical gain of lattice matched III-V dilute nitride bismide quantum wells for 1.55 $μ$m optical communication systems
Dilute nitride bismide GaNBiAs is a potential semiconductor alloy for near- and mid-infrared applications, particularly in 1.55 $\mu$m optical communication systems. Incorporating dilute amounts of Bismuth (Bi) into GaAs reduces the effective bandgap rapidly, while significantly increasing the spin-orbit-splitting ener...
1706.07007v1
2017-10-06
Combined Machine Learning and CALPHAD Approach for Discovering Processing-Structure Relationships in Soft Magnetic Alloys
We aim to investigate relationships between select processing parameters or inputs (composition, temperature, annealing time) and two structural parameters, specifically, the mean radius and volume fraction of the Fe$_3$Si nanocrystals. To this end, we have deviced a combined CALPHAD and machine learning approach that ...
1710.02605v4
2018-04-04
Crystal plasticity simulation of the effect of grain size on the fatigue behavior of polycrystalline Inconel 718
A microstructure-based model that accounts for the effect of grain size has been developed to study the effect of grain size on the fatigue life of Inconel 718 alloys. The fatigue behavior of two alloys with different grain size was determined by means of uniaxial cyclic deformation tests under fully-reversed deformati...
1804.01515v2
2019-03-22
Artificial intelligence-based process for metal scrap sorting
Machine learning offers remarkable benefits for improving workplaces and working conditions amongst others in the recycling industry. Here e.g. hand-sorting of medium value scrap is labor intensive and requires experienced and skilled workers. On the one hand, they have to be highly concentrated for making proper readi...
1903.09415v1
2019-09-18
Towards low-loss telecom-wavelength photonic devices by designing GaBi$_{x}$As$_{1-x}$/GaAs core$-$shell nanowires
Nanowires are versatile nanostructures, which allow an exquisite control over bandgap energies and charge carrier dynamics making them highly attractive as building blocks for a broad range of photonic devices. For optimal solutions concerning device performance and cost, a crucial element is the selection of a suitabl...
1909.08312v2
2019-12-23
Towards an understanding of the chemisorption and catalytic activity of Pd$_{X}$Ru$_{1-X}$ nanoparticles using photoelectron spectroscopy
Chemisorption process and catalytic activity of CO to CO2 conversion on PdXRu1-X (X : 0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1) extended as a benchmark for further investigation of very complex nanoparticle (NP) structures have been checked into thoroughly by using the synchrotron-based hard X-ray photoelectron spectroscopy (H...
1912.10681v1
2020-02-04
Magnetic behavior of a ferro-ferrimagnetic ternary alloy AB$_ρ$C$_{1-ρ}$ with a selective site disorder: the case study of a mixed-spin Ising model on a honeycomb lattice
Phase transitions, compensation phenomenon and magnetization of a ferro-ferrimagnetic ternary alloy AB$_{\rho}$C$_{1-\rho}$ composed of three different kinds of magnetic ions A, B and C with the spin magnitude 1/2, 1 and 3/2 are examined within the framework of a mixed-spin Ising model on a honeycomb lattice with a sel...
2002.01572v1
2020-02-06
Reversible Al Propagation in Si$_x$Ge$_{1-x}$ Nanowires
While reversibility is a fundamental concept in thermodynamics, most reactions are not readily reversible, especially in solid state physics. For example, thermal diffusion is a widely known concept, used among others to inject dopant atoms into the substitutional positions in the matrix and improve the device properti...
2002.02373v1
2020-02-18
Microstructure Design of Low-Melting-Point Alloy (LMPA)/ Polymer Composites for Dynamic Dry Adhesion Tuning in Soft Gripping
Tunable dry adhesion is a crucial mechanism in compliant manipulation. The gripping force, mainly originated from the van der Waals force between the adhesive composite and the object to be gripped, can be controlled by reversibly varying the physical properties (e.g., stiffness) of the composite via external stimuli. ...
2002.07882v1
2020-03-03
Filled Carbon Nanotubes as Anode Materials for Lithium-Ion Batteries
Downsizing well-established materials to the nanoscale is a key route to novel functionalities, in particular if different functionalities are merged in hybrid nanomaterials. Hybrid carbon-based hierarchical nanostructures are particularly promising for electrochemical energy storage since they combine benefits of nano...
2003.01379v1
2020-09-12
Ferrimagnetic States of Na-K Alloy Clusters in Zeolite Low-Silica X
In zeolite low-silica X (LSX), beta-cages with the inside diameter of approx 7 AA{} are arrayed in a diamond structure. Among them, supercages with the inside diameter of approx 13 AA{} are formed and arrayed in a diamond structure by the sharing of windows with the inside diameter of approx 8 AA{}. The chemical formul...
2009.05742v1
2020-10-26
Solubility limit of Ge Dopants in AlGaN: a Chemical and Microstructural Investigation down to the Nanoscale
Attaining low resistivity AlGaN layers is the keystone to improve the efficiency of light emitting devices in the ultraviolet spectral range. Here, we present a microstructural analysis of Ge-doped AlGaN samples with Al mole fraction from x=0 to 1, and nominal doping level in the range of 1E20 cm-3, together with the m...
2010.13577v1
2020-12-01
$γ$-phase Inclusions as Common Defects in Alloyed $β$-(Al$_x$Ga$_{1\text{-}x}$)$_2$O$_3$ and Doped $β$-Ga$_2$O$_3$ Films
$\beta$-Ga$_2$O$_3$ is a promising ultra-wide bandgap semiconductor whose properties can be further enhanced by alloying with Al. Here, using atomic-resolution scanning transmission electron microscopy (STEM), we find the thermodynamically-unstable $\gamma$-phase is a ubiquitous defect in both $\beta$-(Al$_x$Ga$_{1\tex...
2012.00263v1
2020-12-08
Large magneto-optical effect and magnetic anisotropy energy in two-dimensional metallic ferromagnet Fe$_3$GeTe$_2$
Few layers Fe$_3$GeTe$_2$ is currently the only atomically thin ferromagnetic metal, and thus has drawn huge attention in the field of two-dimensional (2D) magnetism. In this paper, we perform a systematic first principle study on the electronic structure, magnetic anisotropy energy (MAE), and magneto-optical (MO) effe...
2012.04285v2
2020-12-21
Reduced lasing thresholds in GeSn microdisk cavities with defect management of the optically active region
GeSn alloys are nowadays considered as the most promising materials to build Group IV laser sources on silicon (Si) in a full complementary metal oxide semiconductor-compatible approach. Recent GeSn laser developments rely on increasing the band structure directness, by increasing the Sn content in thick GeSn layers gr...
2012.11262v1
2021-01-28
Temperature dependence of magnetization processes in Sm(Co,Fe,Cu,Zr)$_z$ magnets with different nanoscale microstructures
The characteristic microstructure of Sm(Co,Fe,Cu,Zr)$_z$ alloys with SmCo$_5$ cell walls in Sm$_2$Co$_{17}$ cells, all intersected by Zr-rich platelets, makes them some of the best performing high-temperature permanent magnets. Plentiful research has been performed to tailor the microstructure at the nanoscale, but due...
2101.12076v1
2021-10-08
High Spatial Resolution Neutron Transmission Imaging Using a Superconducting Two-Dimensional Detector
Neutron imaging is one of the most powerful tools for nondestructive inspection owing to the unique characteristics of neutron beams, such as high permeability for many heavy metals, high sensitivity for certain light elements, and isotope selectivity owing to a specific nuclear reaction between an isotope and neutrons...
2110.03976v1
2021-10-12
Mixed Alkali-Ion Transport and Storage in Atomic-Disordered Honeycomb Layered $\rm NaKNi_2TeO_6$
Honeycomb layered oxides constitute an emerging class of materials that show interesting physicochemical and electrochemical properties. However, the development of these materials is still limited. Here, we report the combined use of alkali atoms ($\rm Na$ and $\rm K$) to produce a mixed alkali honeycomb layered oxide...
2110.05879v1
2021-10-15
Performance, Successes and Limitations of Deep Learning Semantic Segmentation of Multiple Defects in Transmission Electron Micrographs
In this work, we perform semantic segmentation of multiple defect types in electron microscopy images of irradiated FeCrAl alloys using a deep learning Mask Regional Convolutional Neural Network (Mask R-CNN) model. We conduct an in-depth analysis of key model performance statistics, with a focus on quantities such as p...
2110.08244v1
2021-11-13
Role of carbon and hydrogen in limiting $n$-type doping of monoclinic (Al$_x$Ga$_{1-x}$)$_2$O$_3$
We use hybrid density functional calculations to assess n-type doping in monoclinic (Al$_x$Ga$_{1-x}$)$_2$O$_3$ alloys. We focus on Si, the most promising donor dopant, and study the structural properties, formation energies and charge-state transition levels of its various configurations. We also explore the impact of...
2111.07194v2
2022-05-19
An Effective Activation Method for Industrially Produced TiFeMn Powder for Hydrogen Storage
This work proposes an effective thermal activation method with low technical effort for industrially produced titanium-iron-manganese powders (TiFeMn) for hydrogen storage. In this context, the influence of temperature and particle size of TiFeMn on the activation process is systematically studied. The results obtained...
2205.09429v2
2022-11-30
Partial crystallization in a Zr-based bulk metallic glass in selective laser melting
Metals in amorphous state are promising for the use as structural materials due to their superior properties related to the absence of grain boundaries and dislocations.Obtaining the amorphous state requires quenching with a high cooling rate.In conventional technologies,this is the reason for a considerable size limit...
2211.17140v1
2023-01-30
Designing magnetocaloric materials for hydrogen liquefaction with light rare-earth Laves phases
Magnetocaloric hydrogen liquefaction could be a "game-changer" for liquid hydrogen industry. Although heavy rare-earth-based magnetocaloric materials show strong magnetocaloric effects in the temperature range required by hydrogen liquefaction (77 ~ 20 K), the high resource criticality of the heavy rare-earth elements ...
2301.12773v4
2023-02-08
Bioabsorbable WE43 Mg alloy wires modified by continuous plasma electrolytic oxidation for implant applications. Part II: degradation and biological performance
The corrosion, mechanical degradation and biological performance of cold-drawn WE43 Mg wires were analyzed as a function of thermo-mechanical processing and the presence of a protective oxide layer created by continuous plasma electrolytic oxidation (PEO). It was found that the corrosion properties of the non-surface-t...
2302.13778v1
2023-02-28
Optimization of Permalloy properties for magnetic field sensors using He$^+$ irradiation
Permalloy, despite being a widely utilized soft magnetic material, still calls for optimization in terms of magnetic softness and magnetostriction for its use in magnetoresistive sensor applications. Conventional annealing methods are often insufficient to locally achieve the desired properties for a narrow parameter r...
2302.14455v2
2023-05-23
Three-dimensional atomic positions and local chemical order of medium- and high-entropy alloys
Medium- and high-entropy alloys (M/HEAs) mix multiple principal elements with near-equiatomic composition and represent a paradigm-shift strategy for designing new materials for metallurgy, catalysis, and other fields. One of the core hypotheses of M/HEAs is lattice distortion. However, experimentally determining the 3...
2305.14123v1
2023-05-29
Ultra-small topological spin textures with size of 1.3nm at above room temperature in Fe78Si9B13 amorphous alloy
Topologically protected spin textures, such as skyrmions1,2 and vortices3,4, are robust against perturbations, serving as the building blocks for a range of topological devices5-9. In order to implement these topological devices, it is necessary to find ultra-small topological spin textures at room temperature, because...
2305.17880v1
2023-06-26
Multiscale insight into the Cd1-xZnxTe vibrational-mechanical properties -- High-pressure experiments and ab initio calculations
The Cd1-xZnxTe semiconductor alloy is a regular system regarding its macroscopic mechanic properties in that its experimental bulk modulus exhibits a linear x-dependence, in line with ab initio predictions. Complexity arises at the bond scale, referring to the intricate Cd1-xZnxTe percolation-type Raman pattern [T. Alh...
2306.14539v1
2023-07-03
A review of uranium-based thin films
Thin films based on silicon and transition-metal elements dominate the semiconducting industry and are ubiquitous in all modern devices. Films have also been produced in the rare-earth series of elements for both research and specialized applications. Thin films of uranium and uranium dioxide were fabricated in the 196...
2307.01018v1
2023-10-11
Absence of topological Hall effect in Fe$_x$Rh$_{100-x}$ epitaxial films: revisiting their phase diagram
A series of Fe$_x$Rh$_{100-x}$ ($30 \leq x \leq 57$) films were epitaxially grown using magnetron sputtering, and were systematically studied by magnetization-, electrical resistivity-, and Hall resistivity measurements. After optimizing the growth conditions, phase-pure Fe$_{x}$Rh$_{100-x}$ films were obtained, and th...
2310.07140v1
2023-10-22
Microstructure evolution and characteristics of laser-clad lightweight refractory NbxMo$_{0.5}$Ti$_{1.5}$Ta$_{0.2}$Cr high-entropy alloy
Lightweight refractory high-entropy alloy coatings (RHEAcs) of NbxMo$_{0.5}$Ti$_{1.5}$Ta$_{0.2}$Cr (where $x=$ 1, 1.3, 1.5, and 2) were fabricated on the surface of 316L stainless steel using laser cladding (LC) technology. A comprehensive study was conducted to elucidate the effect of Nb content on the microstructure,...
2310.14223v1
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...
2311.03088v2
2024-03-01
Electrochemical Evaluation of Mg and a Mg-Al 5%Zn Metal Rich Primers for Protection of Al-Zn-Mg-Cu Alloy in NaCl
High purity magnesium and a Mg-Al 5wt% Zn metal rich primer (MRP) were compared for their ability to suppress intergranular corrosion (IGC) and intergranular stress corrosion cracking (IG-SCC) in peak aged AA 7075-T651 by sacrificial anode-based cathodic prevention. Tests were conducted in 0.6 M NaCl solution under ful...
2403.00610v1
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. ...
2403.04741v1
2024-03-14
Fracture of the $C$15 CaAl$_2$ Laves phase at small length-scales
The cubic $C$15 CaAl$_2$ Laves phase is a crucial brittle intermetallic precipitate in Mg-Al-Ca alloys. Although knowledge of the mechanical properties of coexisting phases is essential for improved alloy design, the fracture toughness is not yet studied experimentally due to the need for miniaturised testing. Here, mi...
2403.09461v1
2024-04-09
Thermoelectric transport and current noise through a multilevel Anderson impurity: Three-body Fermi-liquid corrections in quantum dots and magnetic alloys
We present a comprehensive Fermi-liquid description for thermoelectric transport and current noise, applicable to multilevel quantum dots (QD) and magnetic alloys (MA) without electron-hole or time-reversal symmetry. Our formulation for the low-energy transport is based on an Anderson model with $N$ discrete impurity l...
2404.05947v1
1995-08-17
Reproducible noise in a macroscopic system: magnetic avalanches in Perminvar
A study of magnetic avalanches in Perminvar, an Fe-Ni-Co alloy, shows that some avalanches are almost exactly reproducible from one magnetic field cycle to the next, while others show significant variability. Averaging over many cycles produces a fingerprint reflecting the reproducibility of the noise. The fingerprint ...
9508005v1
2002-11-07
On the origin of irregular structure in Saturn's rings
We suggest that the irregular structure in Saturn's B ring arises from the formation of shear-free ring-particle assemblies of up to ~100 km in radial extent. The characteristic scale of the irregular structure is set by the competition between tidal forces and the yield stress of these assemblies; the required tensile...
0211149v1
1997-04-29
Phase Segregation Dynamics in Particle Systems with Long Range Interactions I: Macroscopic Limits
We present and discuss the derivation of a nonlinear non-local integro-differential equation for the macroscopic time evolution of the conserved order parameter of a binary alloy undergoing phase segregation. Our model is a d-dimensional lattice gas evolving via Kawasaki exchange dynamics, i.e. a (Poisson) nearest-neig...
9705001v1
1992-04-23
Tweed in Martensites: A Potential New Spin Glass
We've been studying the ``tweed'' precursors above the martensitic transition in shape--memory alloys. These characteristic cross--hatched modulations occur for hundreds of degrees above the first--order shape--changing transition. Our two--dimensional model for this transition, in the limit of infinite elastic anisotr...
9204012v1
1993-05-14
Elastic anomaly of heavy fermion systems in a crystalline field
An elastic anomaly, observed in the heavy fermi liquid state of Ce alloys (for example, CeCu$_6$ and CeTe), is analyzed by using the infinite-$U$ Anderson lattice model. The four atomic energy levels are assumed for f-electrons. Two of them are mutually degenerate. A small crystalline splitting $2\Delta$ is assumed bet...
9305013v1
1993-07-13
Theory of Adsorption and Surfactant Effect of Sb on Ag (111)
We present first-principles studies of the adsorption of Sb and Ag on clean and Sb-covered Ag (111). For Sb, the {\it substitutional} adsorption site is found to be greatly favored with respect to on-surface fcc sites and to subsurface sites, so that a segregating surface alloy layer is formed. Adsorbed silver adatoms ...
9307024v1
1993-07-28
Elastic anomaly of heavy fermion systems in a crystalline field II
An elastic anomaly, observed in the heavy Fermi liquid state of Ce alloys (for example, CeCu_6 and CeTe), is analyzed by using the infinite-U Anderson lattice model. Four atomic energy levels are assumed for f-electrons. Two of them are mutually degenerate. A small crystalline splitting 2 Delta is assumed between two e...
9307058v1
1994-04-05
Manifestation of Quantum Chaos in Electronic Band Structures
We use semiconductors as an example to show that quantum chaos manifests itself in the energy spectrum of crystals. We analyze the {\it ab initio} band structure of silicon and the tight-binding spectrum of the alloy $Al_xGa_{1-x}As$, and show that some of their statistical properties obey the universal predictions of ...
9404005v1
1994-06-06
Volume Effect in the Landau Theory of Martensitic Phase Transitions in Cubic Crystals
An effect of the volume change upon proper ferroelastic (martensitic) phase transitions in cubic crystals is considered. Corresponding terms in the Ginzburg-Landau expansion of the Gibbs free energy are analyzed for the first- as well as second-order phase transitions from cubic to tetragonal lattice under the action o...
9406030v2
1994-11-28
Quantum Interference of Coulomb Interaction and Disorder: Phase Shift of Friedel Oscillations and an Instability of the Fermi Sea
We investigate the influence of interference between Coulomb interaction and impurity scattering on the static electronic response $\chi (0,q)$ in disordered metals to leading order in the effective Coulomb interaction. When the transport relaxation time $\tau _{tr}$ is much shorter than the quasiparticle life time, we...
9411122v1
1994-12-05
Theory of One-Channel vs. Multi-Channel Kondo Effects for Ce$^{3+}$ Impurities
We introduce a model for Ce$^{3+}$ impurities in cubic metals which exhibits competition between the Fermi-liquid fixed point of the single channel Kondo model and the non-Fermi-liquid fixed point of the two- and three-channel Kondo models. Using the non-crossing approximation and scaling theory, we find: (i) A possibl...
9412024v2
1995-02-13
Disorder-Driven Pretransitional Tweed in Martensitic Transformations
Defying the conventional wisdom regarding first--order transitions, {\it solid--solid displacive transformations} are often accompanied by pronounced pretransitional phenomena. Generally, these phenomena are indicative of some mesoscopic lattice deformation that ``anticipates'' the upcoming phase transition. Among thes...
9502054v1
1995-08-17
Approximation of excitonic absorption in disordered systems using a compositional component weighted CPA
Employing a recently developed technique of component weighted two particle Green's functions in the CPA of a binary substitutional alloy $A_cB_{1-c}$ we extend the existing theory of excitons in such media using a contact potential model for the interaction between electrons and holes to an approximation which interpo...
9508070v2
1995-08-29
One-, Two-, and Three-channel Kondo effects for a model Ce$^{3+}$ Impurity in a Metal
We present studies of a simple Anderson model Hamiltonian for Ce$^{3+}$ ions in cubic symmetry with three configurations ($f^0$,$f^1$,$f^2$). Our Hamiltonian includes: (i) One-channel Anderson model; (ii) Two-channel Anderson model. Using the third order scaling analysis, we study stability of the non-Fermi liquid fixe...
9508129v1
1993-02-13
Structure of binary clusters: are icosahedra relevant ?
We investigate the structure of 13-particle clusters in binary alloys for various size ratios and different concentrations via MD simulation. Our goal is to predict which systems are likely to form local icosahedral structures when rapidly supercooled from the melt. We calculate the energy spectrum of the minimal energ...
9511107v1
1996-02-07
Proof of phase separation in the binary-alloy problem: the one-dimensional spinless Falicov-Kimball model
The ground states of the one-dimensional Falicov-Kimball model are investigated in the small-coupling limit, using nearly degenerate perturbation theory. For rational electron and ion densities, respectively equal to $\frac{p}{q}$, $\frac{p_i}{q}$, with $p$ relatively prime to $q$ and $\frac{p_i}{q}$ close enough to $\...
9602042v1
1996-06-14
A new non-Fermi liquid fixed point
We study a new exchange interaction in which the conduction electrons with pseudo spin $S_c=3/2$ interact with the impurity spin $S_I=1/2$. Due to the overscreening of the impurity spin by higher conduction electron spin, a new non-trivial intermediate coupling strength fixed point is realized. Using the numerical reno...
9606095v2
1996-07-04
On Metal-Insulator Transitions due to Self-Doping
We investigate the influence of an unoccupied band on the transport properties of a strongly correlated electron system. For that purpose, additional orbitals are coupled to a Hubbard model via hybridization. The filling is one electron per site. Depending on the position of the additional band, both, a metal--to--insu...
9607032v1
1996-08-26
Screening effects in superconductors
The partition function of the Hubbard model with local attraction and long range Coulomb repulsion between electrons is written as a functional integral with an action $A$ involving a pairing field $\Delta$ and a local potential $V$. After integration over $V$ and over fluctuations in $|\Delta|^{2}$, the final form of ...
9608119v1
1996-09-20
Singlet and triplet doped-hole configurations in La_2Cu_0.5Li_0.5O_4
The ordered alloy La_2Li_{0.5}Cu_{0.5}O_4 is found to be a band insulator in local density approximation (LDA) calculations with the unoccupied conduction band having predominantly d_{x^2-y^2}-symmetry and substantial weight in O 2p-orbitals. This is equivalent to a predominant local singlet configuration d^9L or a low...
9609202v1