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2018-10-04 | Anisotropic electrical and thermal magnetotransport in the magnetic semimetal GdPtBi | The half-Heusler rare-earth intermetallic GdPtBi has recently gained
attention due to peculiar magnetotransport phenomena that have been associated
with the possible existence of Weyl fermions, thought to arise from the
crossings of spin-split conduction and valence bands. On the other hand,
similar magnetotransport ph... | 1810.02300v3 |
2019-04-02 | Spin pumping and spin torque in interfacial tailored Co2FeAl/\b{eta}-Ta layers | The Heusler ferromagnetic (FM) compound Co2FeAl interfaced with a high-spin
orbit coupling non-magnetic (NM) layer is a promising candidate for energy
efficient spin logic circuits. The circuit potential depends on the strength of
angular momentum transfer across the FM/NM interface; hence, requiring low spin
memory lo... | 1904.01506v3 |
2019-04-10 | Non-trivial topological valence bands of common diamond and zinc-blende semiconductors | The diamond and zinc-blende semiconductors are well-known and have been
widely studied for decades. Yet, their electronic structure still surprises
with unexpected topological properties of the valence bands. In this joint
theoretical and experimental investigation we demonstrate for the benchmark
compounds InSb and Ga... | 1904.05063v1 |
2019-10-30 | Magnon spectrum of the Weyl semimetal half-Heusler compound GdPtBi | The compound GdPtBi is known as a material where the non-trivial topology of
electronic bands interplays with an antiferromagnetic order, which leads to the
emergence of many interesting magnetotransport phenomena. Although the magnetic
structure of the compound has previously been reliably determined, the magnetic
int... | 1910.13845v2 |
2014-06-03 | Design and discovery of a novel Half-Heusler transparent hole conductor made of all-metallic heavy elements | Metallic conductors that are optically transparent represent a rare breed of
generally contraindicated physical properties that are nevertheless critically
needed for application where both functionalities are crucial. Such rare
materials have traditionally been searched in the general chemical neighborhood
of compound... | 1406.0872v2 |
2014-06-26 | Unusual weak magnetic exchange in two different structure types: YbPt$_2$Sn and YbPt$_2$In | We present the structural, magnetic, thermodynamic, and transport properties
of the two new compounds YbPt$_2$Sn and YbPt$_2$In. X-ray powder diffraction
shows that they crystallize in different structure types, the hexagonal
ZrPt$_2$Al and the cubic Heusler type, respectively. Despite quite different
lattice types, bo... | 1406.6800v2 |
2018-08-16 | Tunnel magneto-Seebeck effect | The interplay of charge, spin and heat transport is investigated in the
fascinating research field of spin caloritronics, the marriage of spintronics
and thermoelectrics. Here, many new spin-dependent thermal transport phenomena
in magnetic nanostructures have been explored in the recent years. One of them
is the tunne... | 1808.05638v2 |
2019-02-20 | On the inexistence of solitons in Einstein-Maxwell-scalar models | Three non-existence results are established for self-gravitating solitons in
Einstein-Maxwell-scalar models, wherein the scalar field is, generically,
non-minimally coupled to the Maxwell field via a scalar function $f(\Phi)$.
Firstly, a trivial Maxwell field is considered, which yields a consistent
truncation of the f... | 1902.07721v3 |
2019-06-14 | Stability of Long-lived Antiskyrmions in Mn-Pt-Sn Material | The lifetime of antiskyrmions at room temperature in a Mn-Pt-Sn tetragonal
Heusler material has been calculated using an atomic scale representation
including nearly a million spins. The evaluation of the pre-exponential factor
in the Arrhenius rate expression for this large system is made possible by an
implementation... | 1906.06383v5 |
2022-02-04 | Bipolar conduction asymmetries lead to ultra-high thermoelectric power factor | Low band gap thermoelectric materials suffer from bipolar effects at high
temperatures, with increased electronic thermal conductivity and reduced
Seebeck coefficient, leading to reduced power factor and low ZT figure of
merit. In this work we show that the presence of strong transport asymmetries
between the conductio... | 2202.02128v1 |
2022-03-04 | In-situ nitriding of Fe2VAl during laser surface remelting to manipulate microstructure and crystalline defects | Tailoring the physical properties of complex materials for targeted
applications requires optimizing the microstructure and crystalline defects
that influence electrical and thermal transport, and mechanical properties.
Laser surface remelting can be used to modify the sub-surface microstructure of
bulk materials and h... | 2203.02209v1 |
2016-03-03 | Room-temperature magnetic topological semimetal state in half-metallic Heusler Co$_2$TiX (X=Si, Ge, or Sn) | Topological semimetals (TSMs) including Weyl semimetals and nodal-line
semimetals are expected to open the next frontier of condensed matter and
materials science. Although the first inversion breaking Weyl semimetal was
recently discovered in TaAs, its magnetic counterparts, i.e., the time-reversal
breaking Weyl and n... | 1603.01255v3 |
2016-12-10 | Chaos and regularity in the doubly magic nucleus 208Pb | High resolution experiments have recently lead to a complete identification
(energy, spin, and parity) of 151 nuclear levels up to an excitation Energy of
Ex= 6.20 MeV in 208Pb. We present a thorough study of the fluctuation
properties in the energy spectra of the unprecedented set of nuclear bound
states. In a first a... | 1612.03260v1 |
2019-05-24 | A first-principles investigation of Topological Phase Transition in face-centred cubic LiMgBi | Topological Insulators (TI) exhibit robust spin-locked dissipationless
Fermion transport along the surface states. In the current study, we use
\textit{first-principles} calculations to investigate a Topological Phase
Transition (TPT) in a Half-Heusler (HH) compound LiMgBi driven by a Volume
Expansive Pressure (VEP) wh... | 1905.10103v2 |
2019-09-04 | Exploring Disorder in the Spin Gapless Semiconductor Mn$_2$CoAl | Since the prediction of spin-gapless semiconducting behaviour in the Heusler
compound Mn$_2$CoAl, evidence of spin-gapless behaviour in thin films has
typically been inferred from magnetotransport measurements. The spin gapless
state is however fragile, and further, band structure calculations indicate
that even a smal... | 1909.02153v1 |
2019-12-13 | Shallow impurity band in ZrNiSn | ZrNiSn and related half Heusler compounds are candidate materials for
efficient thermoelectric energy conversion with a reported thermoelectric
figure-of-merit of n-type ZrNiSn exceeding unity. Progress on p-type materials
has been more limited, which has been attributed to the presence of an impurity
band, possibly re... | 1912.06539v1 |
2019-12-20 | Defect charging and resonant levels in half-Heusler Nb$_{1-x}$Ti$_x$FeSb | We report $^{93}$Nb and $^{121}$Sb NMR and $^{57}$Fe M\"{o}ssbauer studies
combined with DFT calculations of Nb$_{1-x}$Ti$_x$FeSb ($0\leqslant x
\leqslant0.3$), one of the most promising thermoelectric systems for
applications above 1000 K. These studies provide local information about
defects and electronic configurat... | 1912.09643v3 |
2020-03-18 | Neutron diffraction and symmetry analysis of the martensitic transformation in Co-doped Ni$_2$MnGa | Martensitic transformations are strain driven displacive transitions
governing the mechanical and physical properties in intermetallic materials.
This is the case in Ni$_2$MnGa, where the martensite transition is at the heart
of the striking magnetic shape memory and magneto-caloric properties.
Interestingly, the marte... | 2003.08261v1 |
2020-07-27 | Role of magnetic exchange interactions in chiral-type Hall effects of epitaxial Mn$_{x}$PtSn films | Tetragonal Mn-based Heusler compounds feature rich exchange interactions and
exotic topological magnetic textures, such as antiskyrmions, complimented by
the chiral-type Hall effects. This makes the material class interesting for
device applications. We report the relation of the magnetic exchange
interactions to the t... | 2007.13412v1 |
2021-01-22 | Structural and transport properties of 4f electron doped Y1-x(Dy)xPdBi topological semi-metallic thin films | We report the effect of 4f electron doping on structural, electrical and
magneto-transport properties of Dy doped half Heusler Y1-x(Dy)xPdBi (x =0, 0.2,
0.5, 1) thin films grown by pulsed laser deposition. The Dy doping leads to
lattice contraction which increases from 0% for the parent x =0 sample to
approx 1.3% for x... | 2101.09185v2 |
2021-01-29 | Room-temperature antiskyrmions and sawtooth surface textures in a noncentrosymmetric magnet with $S_4$ symmetry | Topological spin textures have attracted much attention both for fundamental
physics and spintronics applications. Among them, antiskyrmions possess a
unique spin configuration with Bloch-type and N\'eel-type domain walls due to
anisotropic Dzyaloshinskii-Moriya interaction (DMI) in the noncentrosymmetric
crystal struc... | 2101.12359v1 |
2021-02-25 | Unidirectional magnetoresistance and spin-orbit torque in NiMnSb | Spin-dependent transport phenomena due to relativistic spin-orbit coupling
and broken space-inversion symmetry are often difficult to interpret
microscopically, in particular when occurring at surfaces or interfaces. Here
we present a theoretical and experimental study of spin-orbit torque and
unidirectional magnetores... | 2102.12838v1 |
2021-10-11 | Absolute calibration of the latent heat of transition using differential thermal analysis | We describe a simple and accurate differential thermal analysis set up to
measure the latent heat of solid state materials undergoing abrupt phase
transitions in the temperature range from 77 K to above room temperature. We
report a numerical technique for the absolute calibration of the latent heat of
the transition, ... | 2110.05046v1 |
2021-11-20 | Skyrmionics in correlated oxides | While chiral magnets, metal-based magnetic multilayers, or Heusler compounds
have been considered as the material workhorses in the field of skyrmionics,
oxides are now emerging as promising alternatives, as they host special
correlations between the spin-orbital-charge-lattice degrees of freedom and/or
coupled ferroic... | 2111.10562v2 |
2021-11-28 | CoFeVSb: A Promising Candidate for Spin Valve and Thermoelectric Applications | We report a combined theoretical and experimental study of a novel quaternary
Heusler system CoFeVSb from the view point of room temperature spintronics and
thermoelectric applications. It crystallizes in cubic structure with small
DO$_3$-type disorder. The presence of disorder is confirmed by room temperature
synchrot... | 2111.14081v1 |
2022-04-19 | Thermoelectric properties of Fe$_{2}$VAl at high temperature region: A combined experimental and theoretical study | Heusler type compounds have long been recognized as potential thermoelectric
(TE) materials. Here, the experimentally observed TE properties of Fe$_{2}$VAl
are understood through electronic structure calculations in the temperature
range of $300-800$ K. The observed value of $S$ is $\sim-$138 $\mu$V/K at 300
K. Then, t... | 2204.08654v1 |
2022-08-24 | The type-I antiferromagnetic Weyl semimetal InMnTi$_2$ | Topological materials have been a main focus of studies in the past decade
due to their protected properties that can be exploited for the fabrication of
new devices. Among them, Weyl semimetals are a class of topological semimetals
with non-trivial linear band crossing close to the Fermi level. The existence
of such c... | 2208.11412v3 |
2023-01-03 | Ab-initio study of phononic thermal conduction in ScAgC half-Heusler | We present a first-principles lattice calculations to comprehend the thermal
expansion $\alpha(T)$ and lattice thermal conductivity $\kappa_{ph}$ of ScAgC.
The obtained positive frequencies of phonon dispersion shows the dynamical
stability of ScAgC in FCC structure. The estimated $\alpha(T)$ from
quasi-harmonic approx... | 2301.01029v1 |
2023-01-19 | Ab initio comparison of spin-transport properties in MgO-spaced ferrimagnetic tunnel junctions based on Mn$_3$Ga and Mn$_3$Al | We report on first-principles spin-polarised quantum transport calculations
(from NEGF+DFT) in MgO-spaced magnetic tunnel junctions (MTJs) based on two
different Mn-based Heusler ferrimagnetic metals, namely Mn$_3$Al and Mn$_3$Ga
in their tetragonal DO$_{22}$ phase. The former is a fully compensated
half-metallic ferri... | 2301.08300v1 |
2023-02-13 | The impact of an interactive visualization and simulation tool on learning quantum physics: Results of an eye-tracking study | Employing scientific practices to obtain and use information is one of the
central facets of next generation science standards. Especially in quantum
technology education, the ability to employ such practices is an essential
skill to foster both academic success and technological development. In order
to help educators... | 2302.06286v1 |
2023-08-20 | A Framework for Curriculum Transformation in Quantum Information Science and Technology Education | The field of Quantum Information Science and Technology (QIST) is booming.
Due to this, many new educational courses and university programs are needed in
order to prepare a workforce for the developing industry. Owing to its
specialist nature, teaching approaches in this field can suffer with being
disconnected from t... | 2308.10371v2 |
1994-10-19 | Ab initio simulations of liquid NaSn alloys: Zintl anions and network formation | Using the Car-Parrinello technique, ab initio molecular dynamics simulations
are performed for liquid NaSn alloys in five different compositions (20, 40,
50, 57 and 80 % sodium). The obtained structure factors agree well with the
data from neutron scattering experiments. The measured prepeak in the structure
factor is ... | 9410074v1 |
1995-08-25 | Relaxation of Thermoremanent Magnetization in Different Magnetic Phases Of Fe-rich $\mbox{$γ$}$-FeNiCr Alloys | The time decay of the thermoremanent magnetization(TRM) of the
$\mbox{Fe}_{80-\mbox{x}}\mbox{Ni}_{\mbox{x}}\mbox{Cr}_{20}$ ($14\leq \mbox{x}
\leq 30$) alloys has been measured for four different magnetic phases within
the fcc $\mbox{$\gamma$}$-phase using a SQUID magnetometer. In the spin-glass
phase(SG)(X=19) very dis... | 9508116v1 |
1995-09-27 | Numerical Studies on the Magnetism of Fe-Ni-Mn Alloys in the Invar Region | By means of self-consistent semi-empirical LCAO calculations we study the
itinerant magnetism of (Fe_{0.65}Ni_{0.35})_{1-y} Mn_y alloys for y between 0
and 0.22 at T=0 K, neglecting only the transverse spin components. We find that
the magnetic behaviour is quite complicated on a local scale. In addition to
ferromagnet... | 9509167v1 |
1996-03-07 | Droplet Free Energy Functional for the Morphology of Martensites | Martensites are metastable phases, possessing a characteristic morphology,
usually formed during a fast quench accross a structural transition. We attempt
to understand these morphological features using a coarsegrained free energy
functional ${\cal F}[\epsilon ; \Phi]$ which contains, in addition to the usual
strain f... | 9603049v1 |
1996-09-25 | Surface Critical Behavior of Binary Alloys and Antiferromagnets: Dependence of the Universality Class on Surface Orientation | The surface critical behavior of semi-infinite
(a) binary alloys with a continuous order-disorder transition and
(b) Ising antiferromagnets in the presence of a magnetic field is considered.
In contrast to ferromagnets, the surface universality class of these systems
depends on the orientation of the surface with r... | 9609245v2 |
1996-12-17 | Kondo disorder: a possible route towards non-Fermi liquid behavior | We present a general model of disorder in Kondo alloys that, under certain
conditions, leads to non-Fermi liquid behavior. The central underlying idea is
the presence of a distribution of local Kondo temperature scales. If this
distribution is broad enough, such that there are sites with arbitrarily low
Kondo temperatu... | 9612160v1 |
1997-03-10 | Kinetics of Joint Ordering and Decomposition in Binary Alloys | We study phase segregation in a model alloy undergoing both ordering and
decomposition, using computer simulations of Kawasaki exchange dynamics on a
square lattice. Following a quench into the miscibility gap we observe an early
stage in which ordering develops while the composition remains almost uniform.
Then decomp... | 9703094v1 |
1997-04-02 | Effect of the vacancy interaction on the antiphase domain growth process in a two dimensional binary alloy | The influence of diffusing vacancies on the antiphase domain growth process
in a binary alloy is studied by Monte Carlo simulations. The system is modelled
by means of a Blume-Emery-Griffiths hamiltonian with a biquadratic coupling
parameter K controlling the microscopic interactions between vacancies. We
obtain that, ... | 9704013v1 |
1997-07-29 | Spin-Orbit-Induced Magnetic Anisotropy for Impurities in Metallic Samples II. Finite Size Dependence in the Kondo Resistivity | The electrical resistivity including the Kondo resistivity increase at low
temperature is calculated for thin films of dilute magnetic alloys. Assuming
that in the non-magnetic host the spin-orbit interaction is strong like in Au
and Cu, the magnetic impurities have a surface anisotropy calculated in part I.
That aniso... | 9707299v1 |
1997-07-31 | Surface critical behavior of bcc binary alloys | The surface critical behavior of bcc binary alloys undergoing a continuous
B2-A2 order-disorder transition is investigated in the mean-field (MF)
approximation. Our main aim is to provide clear evidence for the fact that
surfaces which break the two-sublattice symmetry generically display the
critical behavior of the N... | 9707345v1 |
1997-09-10 | Thermal and Mechanical Properties of some FCC Transition Metals and their Binary Alloys | The temperature dependence of thermodynamic and mechanical properties of six
fcc transition metals (Ni, Cu, Ag, Au, Pt, Rh) and the alloying behavior of
Ag-Au and Cu-Ni are studied using molecular dynamics (MD). The structures are
described at elevated temperatures by the force fields developed by Sutton and
co-workers... | 9709114v1 |
1997-10-08 | Theory for the electromigration wind force in dilute alloys | A multiple scattering formulation for the electromigration wind force on
atoms in dilute alloys is developed. The theory describes electromigration via
a vacancy mechanism. The method is used to calculate the wind valence for
electromigration in various host metals having a close-packed lattice
structure, namely alumin... | 9710072v1 |
1997-10-13 | Non-Fermi liquid behavior and Griffiths phase in {\it f}-electron compounds | We study the interplay among disorder, RKKY and Kondo interactions in {\it
f}-electron alloys. We argue that the non-Fermi liquid behavior observed in
these systems is due to the existence of a Griffiths phase close to a quantum
critical point. The existence of this phase provides a unified picture of a
large class of ... | 9710123v2 |
1998-02-19 | Ferroelectric effects in PZT | First-principles calculations are performed to investigate alloying and
ferroelectric effects in lead zirconate titanate (PZT) with high Ti
composition. We find that the main effect of alloying in the paraelectric phase
of PZT is the existence of two sets of B-O bonds, i.e., shorter Ti-O bonds vs.
longer Zr-O bonds. On... | 9802209v1 |
1998-03-13 | The Electromigration Force in Metallic Bulk | The voltage induced driving force on a migrating atom in a metallic system is
discussed in the perspective of the Hellmann-Feynman force concept, local
screening concepts and the linear-response approach. Since the force operator
is well defined in quantum mechanics it appears to be only confusing to refer
to the Hellm... | 9803172v1 |
1998-06-07 | Volume changes in binary alloy ordering, a binary classical density functional theory approach | The chemical ordering transition in a binary alloy is examined using
classical density functional theory for a binary mixture. The ordered lattice
is assumed to be obtained from the disordered lattice by a volume change only,
as in L1_2 ordering from an face centered cubic chemically disordered crystal.
Using the simpl... | 9806093v1 |
1998-07-15 | Exactly solvable toy models of unconventional magnetic alloys: Bethe Ansatz versus Renormalization Group method | We propose toy models of unconventional magnetic alloys, in which the density
of band states, $\rho(\epsilon)$, and hybridization, $t(\epsilon)$, are energy
dependent; it is assumed, however, that
$t^2(\epsilon)\propto\rho^{-1}(\epsilon)$, and hence an effective
electron-impurity coupling $\Gamma(\epsilon)=\rho(\epsilo... | 9807231v2 |
1998-10-28 | Theory of Doping and Defects in III-V Nitrides | Doping problems in GaN and in AlGaN alloys are addressed on the basis of
state-of-the-art first-principles calculations. For n-type doping we find that
nitrogen vacancies are too high in energy to be incorporated during growth, but
silicon and oxygen readily form donors. The properties of oxygen, including
DX-center fo... | 9810385v1 |
1999-02-10 | Non-Fermi Liquid Behavior in a Disordered Kondo Alloy Model | We study a mean-field model of a Kondo alloy using numerical techniques and
analytic approximations. In this model, randomly distributed magnetic
impurities interact with a band of conduction electrons and have a residual
RKKY coupling of strength $J$. This system has a quantum critical point at
$J=J_{c} \sim T_{K}^0$,... | 9902139v2 |
1999-03-03 | Theory of magnetoresistance in films of dilute magnetic alloys | Earlier a magnetic anisotropy for magnetic impurities nearby the surface of
non-magnetic host was proposed in order to explain the size dependence of the
Kondo effect in dilute magnetic alloys. Recently Giordano has measured the
magnetoresistance of dilute Au(Fe) films for different thicknesses well above
the Kondo tem... | 9903054v2 |
1999-05-14 | Magnetic hysteresis in the Cu-Al-Mn intermetallic alloy: experiments and modeling | We study isothermal magnetization processes in the Cu-Al-Mn intermetallic
alloy. Hysteresis is observed at temperatures below the spin-freezing of the
system. The characteristics of the hysteresis cycles as a function of
temperature and Mn content (magnetic element) are obtained. At low temperature
(5 K) a change from ... | 9905204v1 |
1999-06-18 | Spinodal decomposition of an ABv model alloy: Patterns at unstable surfaces | We develop mean-field kinetic equations for a lattice gas model of a binary
alloy with vacancies (ABv model) in which diffusion takes place by a vacancy
mechanism. These equations are applied to the study of phase separation of
finite portions of an unstable mixture immersed in a stable vapor. Due to a
larger mobility ... | 9906301v1 |
1999-08-09 | Magnetic anisotropy, first-order-like metamagnetic transitions and large negative magnetoresistance in the single crystal of Gd$_{2}$PdSi$_3$ | Electrical resistivity ($\rho$), magnetoresistance (MR), magnetization,
thermopower and Hall effect measurements on the single crystal
Gd$_{2}$PdSi$_3$, crystallizing in an AlB$_2$-derived hexagonal structure are
reported. The well-defined minimum in $\rho$ at a temperature above N\'eel
temperature (T$_N$= 21 K) and la... | 9908128v1 |
1999-08-25 | The virtual crystal approximation revisited: Application to dielectric and piezoelectric properties of perovskites | We present an approach to the implementation of the virtual crystal
approximation (VCA) for the study of properties of solid solutions in the
context of density-functional methods. Our approach can easily be applied to
any type of pseudopotential, and also has the advantage that it can be used to
obtain estimates of th... | 9908364v1 |
1999-11-18 | Local structure of In_(0.5)Ga_(0.5)As from joint high-resolution and differential pair distribution function analysis | High resolution total and indium differential atomic pair distribution
functions (PDFs) for In_(0.5)Ga_(0.5)As alloys have been obtained by high
energy and anomalous x-ray diffraction experiments, respectively. The first
peak in the total PDF is resolved as a doublet due to the presence of two
distinct bond lengths, In... | 9911293v1 |
2000-01-10 | Connection between charge transfer and alloying core-level shifts based on density-functional calculations | The measurement of alloying core-level binding energy (CLBE) shifts has been
used to give a precise meaning to the fundamental concept of charge transfer.
Here, ab-initio density-functional calculations for the intermetallic compound
MgAu are used to investigate models which try to make a connection between the
core le... | 0001099v1 |
2000-01-12 | Incommensurate and Commensurate Antiferromagnetic Spin Fluctuations in Cr and Cr Alloys from Ab Initio Dynamical Spin Susceptibility Calculations | A scheme for making ab-initio calculations of the dynamic paramagnetic spin
susceptibilities of solids at finite temperatures is described. It is based on
Time-Dependent Density Functional Theory and employs an electronic multiple
scattering formalism. Incommensurate and commensurate anti-ferromagnetic spin
fluctuation... | 0001160v1 |
2000-04-06 | Peculiarities of structural changes in Pd and Pd-alloys | It has been discovered that kinetics of structural changes in Pd and
Pd-alloys under the influence of dissolved hydrogen seems to be non-trivial. As
a rule, structural changes in these systems include correlation changes of
co-existing phases concentration and the defect structure character. These
changes have the stag... | 0004097v1 |
2000-05-08 | Fermi Surface Properties of Low Concentration Ce$_{x}$La$_{1-x}$B$_{6}$: dHvA | The de Haas-van Alphen effect is used to study angular dependent extremal
areas of the Fermi Surfaces (FS) and effective masses of Ce$_{x}$La$_{1-x}$B$%
_{6}$ alloys for $x$ between 0 and 0.05. The FS of these alloys was previously
observed to be spin polarized at low Ce concentration ($x$ = 0.05). This work
gives the ... | 0005147v1 |
2000-05-24 | An anomalous alloy: Y_x Si_{1-x} | We study via density functional-based molecular dynamics the structural and
dynamical properties of the rare earth silicon amorphous alloy Y_xSi_{1-x} for
x=0.093 and x=0.156. The Si network forms cavities in which a Y^{3+} cation is
entrapped. Its electrons are transferred to the Si network and are located in
the dang... | 0005411v1 |
2000-05-28 | Details of disorder matter in 2D d-wave superconductors | We demonstrate that discrepancies between predicted low-energy quasiparticle
properties in disordered 2D d-wave superconductors occur because of the
unanticipated importance of disorder model details and normal-state
particle-hole symmetry. This conclusion follows from numerically exact
evaluations of the quasiparticle... | 0005487v1 |
2000-06-16 | Spin fluctuations in nearly magnetic metals from ab-initio dynamical spin susceptibility calculations:application to Pd and Cr95V5 | We describe our theoretical formalism and computational scheme for making
ab-initio calculations of the dynamic paramagnetic spin susceptibilities of
metals and alloys at finite temperatures. Its basis is Time-Dependent Density
Functional Theory within an electronic multiple scattering, imaginary time
Green function fo... | 0006268v1 |
2000-06-26 | Computer simulation of the microstructure and rheology of semi-solid alloys under shear | The rheological behavior of metallic alloys containing both solid and liquid
phases is investigated in the low solid fraction range (<50%). This behavior
depends on both the solid fraction and the shear rate. The concept of Effective
Volume Fraction (EVF) is used to decorrelate the influence of these two
parameters. At... | 0006405v1 |
2000-07-18 | Shape-induced magnetic anisotropy in dilute magnetic alloys | We extend the theory of the surface-induced magnetic anisotropy to mesoscopic
samples with arbitrary geometry. The shape-induced anisotropy of impurity spins
in small brick-shaped grains of dilute magnetic alloys is studied in detail.
The surface-induced blocking of a magnetic-impurity spin is shown to be very
sensitiv... | 0007294v1 |
2000-08-31 | Ab Initio Molecular Dynamics Simulation of Liquid Ga_xAs_{1-x} Alloys | We report the results of ab initio molecular dynamics simulations of liquid
Ga_xAs_{1-x} alloys at five different concentrations, at a temperature of 1600
K, just above the melting point of GaAs. The liquid is predicted to be metallic
at all concentrations between x = 0.2 and x = 0.8, with a weak resistivity
maximum ne... | 0008467v1 |
2000-10-27 | Dynamics of mesoscopic precipitate lattices in phase separating alloys under external load | We investigate, via three-dimensional atomistic computer simulations, phase
separation in an alloy under external load. A regular two-dimensional array of
cylindrical precipitates, forming a mesoscopic precipitate lattice, evolves in
the case of applied tensile stress by the movement of mesoscopic lattice
defects. A st... | 0010439v1 |
2000-11-20 | Exchange Effects in the Invar Hardening: $Fe_{0.65}Ni_{0.35}$ as a test case | An increase of the critical resolved shear stress of Invar alloys (Invar
hardening) with a lowering temperature is explained. The effect is caused by a
growth of the exchange interaction between dangling $d$-electron states of
dislocation cores and paramagnetic obstacles (e.g., Ni atoms in FeNi alloys)
which occurs bel... | 0011325v1 |
2000-11-29 | Spontaneous alloying in binary metal microclusters - A molecular dynamics study - | Microcanonical molecular dynamics study of the spontaneous alloying(SA),
which is a manifestation of fast atomic diffusion in a nano-sized metal
cluster, is done in terms of a simple two dimensional binary Morse model.
Important features observed by Yasuda and Mori are well reproduced in our
simulation. The temperature... | 0011481v2 |
2000-12-20 | Glassy Spin Dynamics in Non-Fermi-Liquid UCu_{5-x}Pd_x, x = 1.0 and 1.5 | Local f-electron spin dynamics in the non-Fermi-liquid heavy-fermion alloys
UCu_{5-x}Pd_x, x = 1.0 and 1.5, have been studied using muon spin-lattice
relaxation. The sample-averaged asymmetry function Gbar(t) indicates strongly
inhomogeneous spin fluctuations, and exhibits the scaling Gbar(t,H) =
Gbar(t/H^\gamma) expec... | 0012389v2 |
2000-12-28 | Hybridization Mechanism for Cohesion of Cd-based Quasicrystals | Cohesion mechanism of cubic approximant crystals of newly discovered binary
quasicrystals, Cd$_6$M (M=Yb and Ca), are studied theoretically. It is found
that stabilization due to alloying is obtained if M is an element with
low-lying unoccupied $d$ states. This leads to conclusion that the cohesion of
the Cd-based comp... | 0012485v3 |
2001-02-26 | Transformation Kinetics on Mechanical Alloying | We propose and develop a model as an attempt to describe the local mechanism
of mechanical alloying. This model is based on the observation of global
parameters, such as the volumes of the various phases present in the material,
and their transformations during the process. The model is applied to milled
Fe-Cu and Fe-N... | 0102465v3 |
2001-03-13 | Monte Carlo simulation of subsurface ordering kinetics in an fcc-alloy model | Within the atom-vacancy exchange mechanism in a nearest-neighbor interaction
model we investigate the kinetics of surface-induced ordering processes close
to the (001) surface of an fcc A_3B-alloy. After a sudden quench into the
ordered phase with a final temperature above the ordering spinodal, T_f > T_sp,
the early t... | 0103271v2 |
2001-03-29 | Evolution of Nanoporosity in Dealloying | Dealloying is a common corrosion process during which an alloy is "parted" by
the selective dissolution of the electrochemically more active elements. This
process results in the formation of a nanoporous sponge composed almost
entirely of the more noble alloy constituents . Even though this morphology
evolution proble... | 0103615v1 |
2001-04-27 | Effects of C, Cu and Be substitutions in superconducting MgB2 | Density functional calculations are used to investigate the effects of
partial substitutional alloying of the B site in MgB2 with C and Be alone and
combined with alloying of the Mg site with Cu. The effect of such substitutions
on the electronic structure, electron phonon coupling and superconductivity are
discussed. ... | 0104548v1 |
2001-05-03 | Magnetic phase separation in ordered alloys | We present a lattice model to study the equilibrium phase diagram of ordered
alloys with one magnetic component that exhibits a low temperature phase
separation between paramagnetic and ferromagnetic phases. The model is
constructed from the experimental facts observed in Cu$_{3-x}$AlMn$_{x}$ and it
includes coupling b... | 0105055v1 |
2001-06-03 | Ferromagnetic transition in a double-exchange system with alloy disorder | We study ferromagnetic transition in three-dimensional double-exchange model
containing impurities. The influence of both spin fluctuations and impurity
potential on conduction electrons is described in coherent potential
approximation. In the framework of thermodynamic approach we construct Landau
functional for the s... | 0106032v1 |
2001-07-12 | Augmented space recursion for partially disordered systems | Off-stoichiometric alloys exhibit partial disorder, in the sense that only
some of the sublattices of the stoichiometric ordered alloy become disordered.
This paper puts forward a generalization of the augmented space recursion (ASR)
(introduced earlier by one of us (Mookerjee et al 1997(*))) for systems with
many atom... | 0107245v1 |
2001-11-09 | Growth and Properties of Quaternary Alloy Magnetic Semiconductor (InGaMn)As | We have studied growth and properties of quaternary alloy magnetic
semiconductor (InGaMn)As grown both on GaAs substrates and on InP substrates by
low-temperature molecular-beam epitaxy (LT-MBE). (InGaMn)As thin films were
ferromagnetic below ~30 K, exhibiting strong magneto-optical effect. The
lattice constant of [(In... | 0111163v1 |
2001-11-21 | Structural and Superconducting Transitions in Mg_{1-x}Al_{x}B_2 | From systematic ab initio calculations of the alloy system Mg_{1-x}Al_{x}B_2,
we find a strong tendency for the formation of a superstructure characterized
by Al-rich layers. We also present a simple model, based on calculated energies
and an estimate of the configurational entropy, which suggests that the alloy
has tw... | 0111392v3 |
2002-01-08 | Anisotropic, Fermi-Surface-Induced Variation in T_c in MgB_2 Alloys | Using coherent-potential to describe disorder, Gaspari-Gyorffy approach to
evaluate electron-phonon coupling, and Allen-Dynes equation to calculate T_c,
we show that in Mg_{1-x}M_{x}B_{2} (M = Al,Li or Zn) alloys (i) the way T_c
changes depends on the location of the added/modified k-resolved states on the
Fermi surfac... | 0201093v1 |
2002-01-08 | Effects of Disorder in Mg_{1-x}Ta_{x}B_2 Alloys using Coherent-Potential Approximation | Using Korringa-Kohn-Rostoker coherent-potential approximation in the
atomic-sphere approximation (KKR-ASA CPA) method for taking into account the
effects of disorder, Gaspari-Gyorffy formalism for calculating the
electron-phonon coupling constant $\lambda$, and Allen-Dynes equation for
calculating T_c, we have studied ... | 0201094v2 |
2002-02-26 | First-order transition between a small-gap semiconductor and a ferromagnetic metal in the isoelectronic alloys FeSi$_{1-x}$Ge$_x$ | The contrasting groundstates of isoelectronic and isostructural FeSi and FeGe
can be explained within an extended local density approximation scheme (LDA+U)
by an appropriate choice of the onsite Coulomb repulsion, $U$ on the Fe-sites.
A minimal two-band model with interband interactions allows us to obtain a
phase dia... | 0202474v1 |
2002-03-18 | Above-Room-Temperature Ferromagnetism in GaSb/Mn Digital Alloys | Digital alloys of GaSb/Mn have been fabricated by molecular beam epitaxy.
Transmission electron micrographs showed good crystal quality with individual
Mn-containing layers well resolved; no evidence of 3D MnSb precipitates was
seen in as-grown samples. All samples studied exhibited ferromagnetism with
temperature depe... | 0203361v1 |
2002-05-23 | Instability and decomposition on the surface of strained alloy films | A continuum dynamical model is developed to determine the morphological and
compositional instabilities on the free surface of heteroepitaxial alloy films
in the absence of growth. We use linear stability analysis to study the early
nonequilibrium processes of surface evolution, and calculate the stability
conditions a... | 0205493v1 |
2002-05-27 | Microscopical derivation of Ginzburg-Landau-type functionals for alloys and their application to studies of antiphase and interphase boundaries | The earlier-described cluster methods are used to generalize the
Ginzburg-Landau gradient expansion for the free energy of an inhomogeneous
alloy to the case of not small values of order parameters and variations of
composition. The results obtained reveale a number of important differences
with the expressions used in... | 0205573v3 |
2002-06-26 | Comparative Study of Dense Bulk MgB$_2$ Materials Prepared by Different Methods | We report on the results of a comparative investigation of highly dense bulk
MgB$_2$ samples prepared by three methods: (i) hot deformation; (ii) high
pressure sintering; and (iii) mechanical alloying of Mg and B powders with
subsequent hot compaction. All types of samples were studied by
ac-susceptibility, dc-magnetiz... | 0206513v1 |
2002-09-24 | The pseudo-binary mercury chalcogenide alloy HgSe0.7S0.3 at high pressure: a mechanism of the zinc blende/cinnabar reconstructive phase transition | The structure of the pseudo-binary mercury chalcogenide alloy HgSe0.7S0.3 has
been studied by means of X-ray and neutron powder diffraction at pressures up
to 8.5 GPa. A phase transition from the cubic zinc blende structure to the
hexagonal cinnabar structure was observed at P ~ 1 GPa. A phenomenological
model of this ... | 0209548v2 |
2002-09-30 | Magnetotransport properties of a polarization-doped three-dimensional electron slab | We present evidence of strong Shubnikov-de-Haas magnetoresistance
oscillations in a polarization-doped degenerate three-dimensional electron slab
in an Al$_{x}$Ga$_{1-x}$N semiconductor system. The degenerate free carriers
are generated by a novel technique by grading a polar alloy semiconductor with
spatially changing... | 0209664v2 |
2002-10-14 | Ferromagnetism and Metal-Insulator Transition in the Disordered Hubbard Model | A detailed study of the paramagnetic to ferromagnetic phase transition in the
one-band Hubbard model in the presence of binary alloy disorder is presented.
The influence of the disorder (with concentration $x$ and $1-x$ of the two
alloy ions) on the Curie temperature $T_{c}$ is found to depend strongly on
electron dens... | 0210296v1 |
2002-11-14 | Synthesis and Properties of YbB2 | We report temperature and field dependent measurements of the magnetic
susceptibility, specific heat and resistivity of sintered YbB2 pellets,
prepared via two distinct reaction routes, utilizing different temperatures,
pressures and sintering times. Sample behavior is affected by the preparation
procedure, as a conseq... | 0211288v1 |
2002-11-18 | Optimizing thermal transport in the Falicov-Kimball model: binary-alloy picture | We analyze the thermal transport properties of the Falicov-Kimball model
concentrating on locating regions of parameter space where the thermoelectric
figure-of-merit ZT is large. We focus on high temperature for power generation
applications and low temperature for cooling applications. We constrain the
static particl... | 0211385v1 |
2002-12-18 | Coexistence of ferro- and antiferromagnetic order in Mn-doped Ni$_2$MnGa | Ni-Mn-Ga is interesting as a prototype of a magnetic shape-memory alloy
showing large magnetic field induced strains. We present here results for the
magnetic ordering of Mn-rich Ni-Mn-Ga alloys based on both experiments and
theory. Experimental trends for the composition dependence of the magnetization
are measured by... | 0212442v1 |
2003-02-03 | Bonding in MgSi and AlMgSi Compounds Relevant to AlMgSi Alloys | The bonding and stability of MgSi and AlMgSi compounds relevant to AlMgSi
alloys is investigated with the use of (L)APW+(lo) DFT calculations. We show
that the $\beta$ and $\beta''$ phases found in the precipitation sequence are
characterised by the presence of covalent bonds between Si-Si nearest neighbour
pairs and c... | 0302027v1 |
2003-02-05 | Using bond-length dependent transferable force constants to predict vibrational entropies in Au-Cu, Au-Pd, and Cu-Pd alloys | A model is tested to rapidly evaluate the vibrational properties of alloys
with site disorder. It is shown that length-dependent transferable force
constants exist, and can be used to accurately predict the vibrational entropy
of substitutionally ordered and disordered structures in Au-Cu, Au-Pd, and
Cu-Pd. For each re... | 0302109v1 |
2003-04-17 | The three-dimensional Anderson model of localization with binary random potential | We study the three-dimensional two-band Anderson model of localization and
compare our results to experimental results for amorphous metallic alloys
(AMA). Using the transfer-matrix method, we identify and characterize the
metal-insulator transitions as functions of Fermi level position, band
broadening due to disorder... | 0304390v1 |
2003-04-24 | Room Temperature Electrochemical Synthesis of Hg-1212 Superconducting Thin Films | In the present investigation, the novel two-step electrochemical process of
room temperature synthesis of Hg-1212 superconducting films has been developed
and reported first time. Electrochemical parameters were optimized by studying
cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry
(CA) for... | 0304566v1 |
2003-07-01 | Growth and properties of ferromagnetic In(1-x)Mn(x)Sb alloys | We discuss a new narrow-gap ferromagnetic (FM) semiconductor alloy,
In(1-x)Mn(x)Sb, and its growth by low-temperature molecular-beam epitaxy. The
magnetic properties were investigated by direct magnetization measurements,
electrical transport, magnetic circular dichroism, and the magneto-optical Kerr
effect. These data... | 0307032v1 |
2003-07-09 | Frequency Dependence of Magnetoelectric Interactions in Layered Structures of Ferromagnetic Alloys and Piezoelectric Oxides | Magnetoelectric (ME) interactions in layered structures of magnetostrictive
and piezoelectric phases are mediated by mechanical deformation. Here we
discuss the frequency dependence of ME coupling in bilayers and trilayers of
Permendur, a ferromagnetic alloy, and lead zirconate titanate. Data on ME
voltage coefficient ... | 0307208v1 |
2003-07-29 | Vibrational properties of phonons in random binary alloys: An augmented space recursive technique in the k-representation | We present here an augmented space recursive technique in the
k-representation which include diagonal, off-diagonal and the environmental
disorder explicitly : an analytic, translationally invariant, multiple
scattering theory for phonons in random binary alloys.We propose the augmented
space recursion (ASR) as a compu... | 0307697v2 |
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