publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2003-08-25 | New group of stable icosahedral quasicrystals: structural properties and formation conditions | Structural studies on the icosahedral quasicrystals in Zn-Mg-Sc, Cu-Ga-Mg-Sc,
and Zn-Mg-Ti alloys as well as their corresponding 1/1 cubic approximants, have
revealed that these quasicrystals belong to a new structural group similar to
Cd-based quasicrystals. This group is characterized by a triple-shell
icosahedral cl... | 0308478v1 |
2003-09-02 | Mott-Hubbard metal-insulator transition at non-integer filling | Correlated electrons in a binary alloy $A_{x}B_{1-x}$ are investigated within
the Hubbard model and dynamical mean--field theory (DMFT). The random energies
$\epsilon_{i}$ have a bimodal probability distribution and an energy separation
$\Delta $. We solve the DMFT equations by the numerical renormalization group
metho... | 0309067v1 |
2003-09-02 | Low temperature irreversibility induced by thermal cycles on two prototypical phase separated manganites | We have studied the effect of irreversibility induced by repeated thermal
cycles on the electric transport and magnetization of polycrystalline samples
of La0.5Ca0.5MnO3 and La0.325Pr0.3Ca0.375MnO3. An increase of the resistivity
and a decrease of the magnetization at different temperature ranges after
cycling is obtai... | 0309073v2 |
2003-09-12 | Anisotropy of exchange stiffness and its effect on the properties of magnets | Using the spin-spiral formulation of the tight-binding linear muffin-tin
orbital method, the principal components of the exchange stiffness tensor are
calculated for typical hard magnets including tetragonal CoPt-type and
hexagonal YCo5 alloys. The exchange stiffness is strongly anisotropic in all
studied alloys. This ... | 0309321v1 |
2003-10-24 | Reliable First-Principles Alloy Thermodynamics via Truncated Cluster Expansions | In alloys cluster expansions (CE) are increasingly used to combine
first-principles electronic-structure and Monte Carlo methods to predict
thermodynamic properties. As a basis-set expansion in terms of lattice
geometrical clusters and effective cluster interactions, the CE is exact if
infinite, but is tractable only i... | 0310584v2 |
2003-12-15 | First order magnetic transition in CeFe$_2$ alloys: Phase-coexistence and metastability | First order ferromagnetic (FM) to antiferromagnetic (AFM) phase transition in
doped-CeFe$_2$ alloys is studied with micro-Hall probe technique. Clear visual
evidence of magnetic phase-coexistence on micrometer scales and the evolution
of this phase-coexistence as a function of temperature, magnetic field and time
acros... | 0312352v1 |
2004-01-30 | High-field superconductivity in alloyed MgB2 thin films | We investigated the effect of alloying on the upper critical field $H_{c2}$
in 12 $MgB_2$ films, in which disorder was introduced by growth, carbon doping
or He-ion irradiation, finding a significant $H_{c2}$ enhancement in C-alloyed
films, and an anomalous upward curvature of $H_{c2}(T)$. Record high values of
$H_{c2}... | 0402001v1 |
2004-05-09 | Electronic structure of random binary alloys : an augmented space formulation in reciprocal space | We present here a reciprocal space formulation of the Augmented space
recursion (ASR) which uses the lattice translation symmetry in the full
augmented space to produce configuration averaged quantities, such as spectral
functions and complex band structures. Since the real space part is taken into
account {\sl exactly... | 0405175v2 |
2004-05-09 | Dislocation Formation and Work-Hardening in Two-Phase Alloys | A phase field model is presented to investigate dislocation formation
(coherency loss) and workhardening in two-phase binary alloys. In our model the
elastic energy density is a periodic function of the shear and tetragonal
strains, which allows multiple formation of slips (dislocation dipoles). By
numerically integrat... | 0405177v3 |
2004-05-17 | Disordered Carbon nanotube alloys in the Effect Medium Super Cell Approximation | We investigate a disordered single-walled carbon nanotube (SWCNT) in an
effective medium super cell approximation (EMSCA).
First type of disorder that we consider is the presence of vacancies.
Our results show that the vacancies induce some bound states on their
neighbor host sites, leading to the creation of a ban... | 0405364v1 |
2004-05-26 | ScGaN Alloy Growth by Molecular Beam Epitaxy: Evidence for a Metastable Layered Hexagonal Phase | Alloy formation in ScGaN is explored using rf molecular beam epitaxy over the
Sc fraction range x = 0-100%. Optical and structural analysis show separate
regimes of growth, namely I) wurtzite-like but having local lattice distortions
in the vicinity of the ScGa substitutions for small x (x < 0.17), II) a
transitional r... | 0405614v2 |
2004-05-26 | Surface pinning in amorphous ZrTiCuNiBe alloy | We have measured the amplitude and the phase of an electromagnetic (EM) field
radiated from superconductor (amorphous ZrTiCuNiBe alloy) in the mixed state
due to interaction of the flux lattice with an elastic wave. The results
undoubtedly point to an essential contribution of a surface pinning into the
flux lattice dy... | 0405616v1 |
2004-06-26 | Wetting behavior at the free surface of a liquid gallium-bismuth alloy: An X-ray reflectivity study close to the bulk monotectic point | We present x-ray reflectivity measurements from the free surface of a liquid
gallium-bismuth alloy (Ga-Bi) in the temperature range close to the bulk
monotectic temperature $T_{mono} = 222$C. Our measurements indicate a
continuous formation of a thick wetting film at the free surface of the binary
system driven by the ... | 0406659v1 |
2004-07-06 | The Diffusion of Sb into Ge without Contamination by Fast Diffusing Electrically Active Impurities | A method has been developed to permit the diffusion of Sb into Ge at high
temperatures (~850 C) without contamination by fast diffusing electrically
active impurities in particular by Cu. A liquid metal alloy is used as a getter
of Cu and other fast diffusing impurities. This alloy, Ga- In eutectic,
completely encloses... | 0407111v5 |
2004-07-11 | Wetting Phase Transition at the Surface of Liquid Ga-Bi alloys: An X-ray Reflectivity Study | X-ray reflectivity measurements of the binary liquid Ga-Bi alloy reveal a
dramatically different surface structure above and below the monotectic
temperature $T_{mono}=222^{\circ}$ C.
A Gibbs-adsorbed Bi monolayer resides at the surface at both regimes.
However, a 30 {\AA} thick, Bi-rich wetting film intrudes between... | 0407270v1 |
2004-07-17 | Composition and strain dependence of band offsets at metamorphic In$_{x}$Ga$_{1-x}$As/In$_{y}$Al$_{1-y}$As heterostructures | We have studied the In$_{x}$Ga$_{1-x}$As/In$_{y}$Al$_{1-y}$As (001) interface
using first-principles ab-initio pseudopotential calculations, focusing on the
effects of alloy composition and strain state on the electronic properties. In
particular we estimate a valence band offset (VBO) of 0.11 eV (InGaAs higher),
inclu... | 0407461v2 |
2004-07-28 | Fractal Self-Assembled Nanostructures on Monocrystalline Silicon Surface | We present ultra-shallow diffusion profiles performed by short-time diffusion
of boron from the gas phase using controlled surface injection of
self-interstitials and vacancies into the n-type Si(100) wafers. The diffusion
profiles of this art are found to consist of both longitudinal and lateral
silicon quantum wells ... | 0407722v1 |
2004-07-30 | Phase stability analysis in Fe-Pt and Co-Pt alloy systems: An augmented space study | We have studied the problem of phase stability in Fe-Pt and Co-Pt alloy
systems. We have used the orbital peeling technique in the conjunction of
augmented space recursion based on the tight binding linear orbital method as
the method for the calculation of pair interaction energies. In particular, we
have generalized ... | 0407805v2 |
2004-09-14 | Kinetic Monte Carlo Simulations of Crystal Growth in Ferroelectric Alloys | The growth rates and chemical ordering of ferroelectric alloys are studied
with kinetic Monte Carlo (KMC) simulations using an electrostatic model with
long-range Coulomb interactions, as a function of temperature, chemical
composition, and substrate orientation. Crystal growth is characterized by
thermodynamic process... | 0409364v1 |
2004-09-30 | Group V Mixing Effects in the Structural and Optical Properties of (ZnSi)1/2(P)1/4(As)1/4 | We present {\it ab initio} total energy and band structure calculations based
on Density Funtional Theory (DFT) within the Local Density Aproximation (LDA)
on group-V mixing effects in the optoelectronic material
$(ZnSi)_{1/2}P_{1/4}As_{3/4}$. This compound has been recently proposed by
theoretical design as an optical... | 0409782v1 |
2004-10-20 | Electronic structure of complex spd Hume-Rothery phases in transition-metal aluminides | The discovery of quasicrystals phases and approximants in Al(rich)-Mn system
has revived the interest for complex aluminides containing transition-metal
atoms. On one hand, it is now accepted that the Hume-Rothery stabilization
plays a crucial role. On the other hand, transition-metal atoms have also a
very important e... | 0410513v2 |
2004-10-21 | The local atomic quasicrystal structure of the icosahedral Mg25Y11Zn64 alloy | A local and medium range atomic structure model for the face centred
icosahedral (fci) Mg25Y11Zn64 alloy has been established in a sphere of r = 27
A. The model was refined by least squares techniques using the atomic pair
distribution (PDF) function obtained from synchrotron powder diffraction. Three
hierarchies of th... | 0410534v1 |
2004-12-05 | Pairing Interactions and Gibbs Adsorption at the Liquid Bi-In Surface: A Resonant X-Ray Reflectivity Study | Resonant x-ray reflectivity measurements from the surface of liquid Bi22In78
find only a modest surface Bi enhancement, with 35 atomic % Bi in the first
atomic layer. This is in contrast to the Gibbs adsorption in all liquid alloys
studied to date, which show surface segregation of a complete monolayer of the
low surfa... | 0412103v1 |
2004-12-05 | Microscopic Surface Structure of Liquid Alkali Metals | We report an x-ray scattering study of the microscopic structure of the
surface of a liquid alkali metal. The bulk liquid structure factor of the
eutectic K67Na33 alloy is characteristic of an ideal mixture, and so shares the
properties of an elemental liquid alkali metal. Analysis of off-specular
diffuse scattering an... | 0412109v1 |
2005-01-03 | Fermi Surface as a Driver for the Shape-Memory Effect in AuZn | Martensites are materials that undergo diffusionless, solid-state
transitions. The martensitic transition yields properties that depend on the
history of the material and may allow it to recover its previous shape after
plastic deformation. This is known as the shape-memory effect (SME). We have
succeeded in identifyin... | 0501024v1 |
2005-01-11 | Photoinduced time-resolved electrodynamics of superconducting metals and alloys | The photoexcited state in superconducting metals and alloys was studied via
pump-probe spectroscopy. A pulsed Ti:sapphire laser was used to create the
non-equilibrium state and the far-infrared pulses of a synchrotron storage
ring, to which the laser is synchronized, measured the changes in the material
optical propert... | 0501253v1 |
2005-02-18 | Accuracy of ab initio methods in predicting the crystal structures of metals: review of 80 binary alloys | Predicting and characterizing the crystal structure of materials is a key
problem in materials research and development. We report the results of ab
initio LDA/GGA computations for the following systems: AgAu, AgCd, AgMg, AgMo*,
AgNa, AgNb*, AgPd, AgRh*, AgRu*, AgTc*, AgTi, AgY, AgZr, AlSc, AuCd, AuMo*,
AuNb, AuPd, AuP... | 0502465v1 |
2005-03-18 | Precipitation kinetics of Al3Zr and Al3Sc in aluminum alloys modeled with cluster dynamics | Precipitation kinetics of Al3Zr and Al3Sc in aluminum supersaturated solid
solutions is studied using cluster dynamics, a mesoscopic modeling technique
which describes the various stages of homogeneous precipitation by a single set
of rate equations. The only parameters needed are the interface free energy and
the diff... | 0503485v2 |
2005-04-12 | Mott transition in the asymmetric Hubbard model at half-filling within dynamical mean-field theory | We apply the approximate analytic methods to the investigation of the band
structure of the asymmetric Hubbard model where the chemical potentials and
electron transfer parameters depend on the electron spin (type of
quasiparticles). The Hubbard-I and alloy-analogy approximations are the
simplest approximations which a... | 0504289v1 |
2005-04-19 | Quantum phases in mixtures of fermionic atoms | A mixture of spin-polarized light and heavy fermionic atoms on a finite size
2D optical lattice is considered at various temperatures and values of the
coupling between the two atomic species. In the case, where the heavy atoms are
immobile in comparison to the light atoms, this system can be seen as a
correlated binar... | 0504491v1 |
2005-04-20 | Correlation regimes in fluctuations of fatigue crack growth | This paper investigates correlation properties of fluctuations in fatigue
crack growth of polycrystalline materials, such as ductile alloys, that are
commonly encountered in structures and machinery components of complex
electromechanical systems. The model of crack damage measure indicates that the
fluctuations of fat... | 0504530v1 |
2005-06-14 | Simulation of the liquid pool for VT3-1 titanium alloy during vacuum arc remelting process | This article describes a simple heat model of the vacuum arc remelting (VAR)
process that includes solution of the nonlinear heat conductivity equation with
the nonlinear boundary conditions which are typical for VAR process. The
finite-difference analogue of the model equations was obtained through the
finite volume m... | 0506314v3 |
2005-06-22 | Differential thermal analysis and solution growth of intermetallic compounds | To obtain single crystals by solution growth, an exposed primary
solidification surface in the appropriate, but often unknown, equilibrium alloy
phase diagram is required. Furthermore, an appropriate crucible material is
needed, necessary to hold the molten alloy during growth, without being
attacked by it. Recently, w... | 0506587v1 |
2005-07-01 | Composition gradients and their effects on superconductivity in Al-doped MgB2 | (Abridged abstract) Alloyed MgB2 differs from pure forms in that diffusion is
needed to distribute the alloying elements homogeneously. Williamson-Hall
analyses of x-ray diffraction peaks showed that Mg1-xAlxB2 samples made by a
typical reaction A had higher crystalline strain than when thoroughly annealed
by reaction ... | 0507041v1 |
2005-07-07 | Generalized band anti-crossing model for highly mismatched semiconductors applied to BeSe$_{x}$Te$_{1 - x}$ | We report a new model for highly mismatched semiconductor (HMS) alloys. Based
on the Anderson impurity Hamiltonian, the model generalizes the recent band
anti-crossing (BAC) model, which successfully explains the band bowing in
highly mismatched semiconductors. Our model is formulated in empirical
tight-binding (ETB) t... | 0507189v2 |
2005-08-05 | Effect of Native Defects on Optical Properties of InxGa1-xN Alloys | The energy position of the optical absorption edge and the free carrier
populations in InxGa1-xN ternary alloys can be controlled using high energy
4He+ irradiation. The blue shift of the absorption edge after irradiation in
In-rich material (x > 0.34) is attributed to the band-filling effect
(Burstein-Moss shift) due ... | 0508140v1 |
2005-08-09 | Spin-dependent recombination in GaAsN alloys | The spin-dependent recombination (SDR) has been observed in GaAs_{1-x}N_{x}
(x = 2.1, 2.7, 3.4%) at room temperature. It reveals itself in a decrease of
the edge photoluminescence (PL) intensity by more than a factor of 3 when
either the polarization of the exciting light is changed from circular to
linear or the trans... | 0508222v1 |
2005-08-22 | Effect of Hydrostatic Pressure on Superconductivity in kappa-[(BEDT-TTF)1-X(Bedse-TTF)X]2Cu[N(CN)2]Br | Static susceptibility of kappa-[(BEDT-TTF)1-x(BEDSe-TTF)x]2Cu[N(CN)2]Br
alloys with the BEDSe-TTF content near the border-line of ambient pressure
superconductivity (x~0.3) has been measured as a function of temperature,
magnetic field, and pressure. A non-monotonic pressure dependence is observed
for both the supercon... | 0508485v1 |
2005-11-23 | Enhancement of the upper critical field of Nb3Sn utilizing disorder introduced by ball milling the elements | Nb3Sn was prepared by milling Nb and Sn powder mixtures followed by limited
reactions to restrict disorder recovery. Although disorder reduced the
superconducting critical temperature Tc, the concomitant electron scattering
increased the upper critical field mu0Hc2 to as high as 35 T at 0 K, as
determined by the Wertha... | 0511560v1 |
2005-11-29 | Free Volume cannot Explain the Spatial Heterogeneity of Debye-Waller factors in a Glass-Forming Binary Alloy | We examine the relation between the free volume per particle and the variance
of the particle position, equivalent to a local Debye-Waller (DW) factor for a
2D glass-forming alloy using molecular dynamics simulations. We find that the
latter quantity exhibits significant spatial heterogeneity despite involving
trajecto... | 0511690v1 |
2006-01-30 | Iron self-diffusion in FeZr/$^{57}$FeZr multilayers measured by neutron reflectometry: Effect of applied compressive stress | Iron self-diffusion in nano-composite FeZr alloy has been investigated using
neutron reflectometry technique as a function of applied compressive stress. A
composite target of (Fe+Zr) and (57Fe+Zr) was alternatively sputtered to
deposit chemically homogeneous multilayer (CHM) structure,
[Fe75Zr25/57Fe75Zr25]10. The mul... | 0601646v1 |
2006-02-01 | Observation of a strongly nested Fermi surface in the shape-memory alloy Ni[0.62]Al[0.38] | The Fermi surface topology of the shape-memory alloy Ni[0.62]Al[0.38] has
been determined using Compton scattering. A large area of this Fermi surface
can be made to nest with other areas by translation through a vector of ~ 0.18
[1,1,0] (2pi/a), which correponds to the wavevector associated with martensitic
precursor ... | 0602028v1 |
2006-02-18 | Scaling Behavior of Portevin-Le Chatelier Effect | The scaling behavior of the Portevin-Le Chatelier (PLC) effect is studied by
deforming a substitutional alloy, Al-2.5%Mg and an interstitial alloy, low
carbon steel (0.15%C, 0.33%Mn, 0.04%P, 0.05%S, 0.15%Si and rest Iron) at room
temperature for a wide range of strain rates. To reveal the exact scaling
nature, the time... | 0602436v1 |
2006-02-19 | (Ga,In)P: A standard alloy in the classification of phonon mode behavior | Contrary to a broadly accepted assumption we show that random (Ga,In)P is not
an exception with respect to the crude classification of the phonon mode
behavior of random mixed crystals in terms of 1-bond->1-mode systems or
2-bond->1-mode systems, as established from the simple criterion derived by
Elliott et al. [Rev.M... | 0602442v1 |
2006-03-22 | Electronic structure and exchange constants in magnetic semiconductors digital alloys: chemical and band-gap effects | First-principles simulations have been performed for [001]-ordered Mn/Ge and
Mn/GaAs "digital alloys", focusing on the effects of i) a larger band-gap and
ii) a different semiconducting host on the electronic structure of the magnetic
semiconductors of interest. Our results for the exchange constants in Mn/Ge,
evaluate... | 0603589v1 |
2006-04-19 | Cluster interactions for fcc-based structures in the Al-Mg-Si system | A class of proposed coherent precipitate structures (Guinier-Preston zones)
in the Al-Mg-Si alloy are investigated using first-principles density
functional theory methods. The cluster expansion method is used to extract
effective interaction parameters, providing the means for large scale energy
calculations of alloy ... | 0604445v1 |
2006-06-09 | Experimental study of the competition between Kondo and RKKY interactions for Mn spins in a model alloy system | The quasicrystal Al-Pd-Mn is a model system for an experimental study of the
competition between Ruderman-Kittel-Kasuya-Yoshida (RKKY) and Kondo
interactions. First, specific of such alloys, only a few Mn atoms carry an
effective spin and their concentration x is tunable over several orders of
magnitude, even though th... | 0606241v1 |
2006-09-19 | Analysis of electron-positron momentum spectra of metallic alloys as supported by first-principles calculations | Electron-positron momentum distributions measured by the coincidence Doppler
broadening method can be used in the chemical analysis of the annihilation
environment, typically a vacancy-impurity complex in a solid. In the present
work, we study possibilities for a quantitative analysis, i.e., for
distinguishing the aver... | 0609461v2 |
2006-11-03 | Energy levels and their correlations in quasicrystals | Quasicrystals can be considered, from the point of view of their electronic
properties, as being intermediate between metals and insulators. For example,
experiments show that quasicrystalline alloys such as AlCuFe or AlPdMn have
conductivities far smaller than those of the metals that these alloys are
composed from. W... | 0611081v1 |
2006-12-27 | Spin-dependent electron dynamics and recombination in GaAs(1-x)N(x) alloys at room temperature | We report on both experimental and theoretical study of conduction-electron
spin polarization dynamics achieved by pulsed optical pumping at room
temperature in GaAs(1-x)N(x) alloys with a small nitrogen content (x = 2.1,
2.7, 3.4%). It is found that the photoluminescence circular polarization
determined by the mean sp... | 0612639v1 |
2007-01-26 | Characterization of irradiated microstructure by X-ray diffraction line profile analysis | Zirconium based alloys have been irradiated with 11 and 15 MeV proton and 116
MeV oxygen ions at different doses. The changes in the microstructure have been
studied for the ion irradiated alloys as a function of dose using X-Ray
Diffraction Line Profile Analysis (XRDLPA) based on the whole powder pattern
fitting techn... | 0701644v1 |
2007-02-08 | X-ray Reflectivity Studies of Atomic-level Surface-segregation in a Liquid Eutectic Alloy of AuSn | X-ray reflectivity studies reveal atomic-level surface-segregation at the
free surface of the eutectic Au71Sn29 liquid alloy. The surface-segregation
extends up to three layers, in which the top layer is almost a pure monolayer
of Sn, the second layer is almost a pure monolayer of Au and the third layer
appears to be s... | 0702193v1 |
2007-02-17 | Crystalline Surface Phases of the Liquid Au-Si Eutectic Alloy | A two dimensional crystalline layer is found at the surface of the liquid
eutectic Au$_{82}$Si$_{18}$ alloy above its melting point $T_M=359 ^{\circ}$C.
Underlying this crystalline layer we find a layered structure, 6-7 atomic
layers thick. This surface layer undergoes a first-order solid-solid phase
transition occurri... | 0702413v2 |
2007-03-26 | Molecular dynamics study on planar clustering of xenon in UO2 | Interatomic potentials of uranium dioxide are investigated on their
applicability to model structural stabilities beyond fluorite phase by
comparing with ab-initio results. A high pressure cotunnite phase and loosely
stacking virtual crystal are involved in order to get a primary confidence for
large-scale deformation ... | 0703657v1 |
1998-11-19 | Modelling of Phase Separation in Alloys with Coherent Elastic Misfit | Elastic interactions arising from a difference of lattice spacing between two
coherent phases can have a strong influence on the phase separation
(coarsening) of alloys. If the elastic moduli are different in the two phases,
the elastic interactions may accelerate, slow down or even stop the phase
separation process. I... | 9811019v1 |
1996-08-29 | Ab initio simulations of liquid systems: Concentration dependence of the electric conductivity of NaSn alloys | Liquid NaSn alloys in five different compositions (20, 40, 50, 57 and 80%
sodium) are studied using density functional calculations combined with
molecular dynamics(Car-Parrinello method). The frequency-dependent electric
conductivities for the systems are calculated by means of the Kubo-Greenwood
formula.
The extrap... | 9608008v1 |
2004-03-08 | Composition-induced structural transitions in mixed rare-gas clusters | The low-energy structures of mixed Ar--Xe and Kr--Xe Lennard-Jones clusters
are investigated using a newly developed parallel Monte Carlo minimization
algorithm with specific exchange moves between particles or trajectories. Tests
on the 13- and 19- atom clusters show a significant improvement over the
conventional bas... | 0403048v2 |
2005-04-05 | Reduction of Magnetic Noise in Atom Chips by Material Optimization | We discuss the contribution of the material type in metal wires to the
electromagnetic fluctuations in magnetic microtraps close to the surface of an
atom chip. We show that significant reduction of the magnetic noise can be
achieved by replacing the pure noble metal wires with their dilute alloys. The
alloy compositio... | 0504027v2 |
2007-04-02 | Effective potentials for quasicrystals from ab-initio data | Classical effective potentials are indispensable for any large-scale
atomistic simulations, and the relevance of simulation results crucially
depends on the quality of the potentials used. For complex alloys like
quasicrystals, however, realistic effective potentials are practically
inexistent. We report here on our ef... | 0704.0163v1 |
2007-04-10 | Magnetic superelasticity and inverse magnetocaloric effect in Ni-Mn-In | Applying a magnetic field to a ferromagnetic Ni$_{50}$Mn$_{34}$In$_{16}$
alloy in the martensitic state induces a structural phase transition to the
austenitic state. This is accompanied by a strain which recovers on removing
the magnetic field giving the system a magnetically superelastic character. A
further property... | 0704.1243v1 |
2007-04-11 | Fracture of complex metallic alloys: An atomistic study of model systems | Molecular dynamics simulations of crack propagation are performed for two
extreme cases of complex metallic alloys (CMAs): In a model quasicrystal the
structure is determined by clusters of atoms, whereas the model C15 Laves phase
is a simple periodic stacking of a unit cell. The simulations reveal that the
basic build... | 0704.1444v1 |
2007-04-19 | Exotic Kondo-hole band resistivity and magnetoresistance of Ce$_{1-x}$La$_{x}$Os$_4$Sb$_{12}$ alloys | Electrical resistivity measurements of non-magnetic single-crystalline
Ce$_{1-x}$La$_x$Os$_4$Sb$_{12}$ alloys, $x=0.02$ and 0.1, are reported for
temperatures down to 20 mK and magnetic fields up to 18 T. At the lowest
temperatures, the resistivity of Ce$_{0.98}$La$_{0.02}$Os$_4$Sb$_{12}$ has a
Fermi-liquid-like temper... | 0704.2581v1 |
2007-06-02 | Local structure evolution in polycrystalline Zn$_{1-x}$Mg$_x$O ($0\leq{x}\leq{0.15}$) studied by Raman and by synchrotron x-ray pair distribution analysis | The local structures of Zn$_{1-x}$Mg$_x$O alloys have been studied by Raman
spectroscopy and by synchrotron x-ray pair distribution function (PDF)
analysis. Within the solid solution range ($0\leq{x}\leq{0.15}$) of
Zn$_{1-x}$Mg$_x$O, the wurtzite framework is maintained with Mg homogeneously
distributed throughout the ... | 0706.0289v1 |
2007-06-05 | Anomalous phonon behavior in the high temperature shape memory alloy: TiPd:Cr | Ti50 Pd50-xCrx is a high temperature shape memory alloy with a martensitic
transformation temperature strongly dependent on the Cr composition. Prior to
the transformation a premartensitic phase is present with an incommensurate
modulated cubic lattice with wave vector of q0=(0.22, 0.22, 0). The temperature
dependence ... | 0706.0737v1 |
2007-07-03 | Numerical study of the influence of an applied electrical potential on the solidification of a binary metal alloy | In this work we study numerically the influence of a homogeneous electrical
field on the fluid and heat transfer phenomena at macroscale and mesoscale
during unidirectional solidification of a binary metal alloy. The numerical
results showed that a pulse electric discharging applied perpendicularly to the
solidificatio... | 0707.0369v1 |
2007-07-19 | Nuclear Georeactor Generation of Earth's Geomagnetic Field | The purpose of this communication is to suggest that the mechanism for
generating the geomagnetic field and the energy source for powering it are one
and the same, a nuclear georeactor at the center of the Earth. Toward this end,
I: i) Present evidence that the nuclear georeactor fission-product sub-shell is
fluid; ii)... | 0707.2850v4 |
2007-08-10 | Low temperature heat capacity of Fe_{1-x}Ga_{x} alloys with large magneostriction | The low temperature heat capacity C_{p} of Fe_{1-x}Ga_{x} alloys with large
magnetostriction has been investigated. The data were analyzed in the standard
way using electron ($\gamma T$) and phonon ($\beta T^{3}$) contributions. The
Debye temperature $\Theta_{D}$ decreases approximately linearly with increasing
Ga conc... | 0708.1432v1 |
2007-08-16 | Dynamic elastic properties and magnetic susceptibility across the austenite-martensite transformation in site-disordered ferromagnetic Ni-Fe-Al alloy | Besides permitting an accurate determination of the
ferromagnetic-to-paramagnetic phase transition temperature and the
characteristic temperatures for the beginning and end of the growth of
martensite (austenite) phase at the expense of austenite (martensite) phase
while cooling (heating), the results of an extensive a... | 0708.2161v1 |
2007-08-23 | Ballistic vs Diffusive Transport in Current-Induced Magnetization Switching | We test whether current-induced magnetization switching due to
spin-transfer-torque in ferromagnetic/non-magnetic/ferromagnetic (F/N/F)
trilayers changes significantly when scattering within the N-metal layers is
changed from ballistic to diffusive. Here ballistic corresponds to a ratio r =
lambda/t greater than or equ... | 0708.3229v2 |
2007-10-24 | Magnetic tight-binding and the iron-chromium enthalpy anomaly | We describe a self consistent magnetic tight-binding theory based in an
expansion of the Hohenberg-Kohn density functional to second order, about a non
spin polarised reference density. We show how a first order expansion about a
density having a trial input magnetic moment leads to the Stoner--Slater rigid
band model.... | 0710.4399v1 |
2007-11-13 | Optimal Wegner estimates for random Schroedinger operators on metric graphs | We consider Schroedinger operators with a random potential of alloy type on
infinite metric graphs which obey certain uniformity conditions. For single
site potentials of fixed sign we prove that the random Schroedinger operator
restricted to a finite volume subgraph obeys a Wegner estimate which is linear
in the volum... | 0711.1953v2 |
2007-11-15 | Labyrinthine Island Growth during Pd/Ru(0001) Heteroepitaxy | Using low energy electron microscopy we observe that Pd deposited on Ru only
attaches to small sections of the atomic step edges surrounding Pd islands.
This causes a novel epitaxial growth mode in which islands advance in a
snakelike motion, giving rise to labyrinthine patterns. Based on density
functional theory toge... | 0711.2491v1 |
2007-12-21 | Effects of hydrostatic pressure on the magnetism and martensitic transition of Ni-Mn-In magnetic superelastic alloys | We report magnetization and differential thermal analysis measurements as a
function of pressure accross the martensitic transition in magnetically
superelastic Ni-Mn-In alloys. It is found that the properties of the
martensitic transformation are significantly affected by the application of
pressure. All transition te... | 0712.3651v1 |
2008-01-12 | $S$-wave pairing symmetry in non-centrosymmetric superconductor Re$_3$W | The alloys of non-centrosymmetric superconductor, Re$_3$W, which were
reported to have an $\alpha$-Mn structure [P. Greenfield and P. A. Beck, J.
Metals, N. Y. \textbf{8}, 265 (1959)] with $T_\mathrm{c}=9 $K were prepared by
arc melting. The ac susceptibility and low-temperature specific heat were
measured on these all... | 0801.1879v1 |
2008-02-08 | Metastability and magnetic memory effect in Ni-Mn-Sn alloy | Magneto-structural instability in the ferromagnetic shape memory alloy of
composition Ni$_2$Mn$_{1.4}$Sn$_{0.6}$ is investigated by transport and
magnetic measurements. Large negative magnetoresistance is observed around the
martensitic transition temperature (90-210 K). Both magnetization and
magnetoresistance data in... | 0802.1102v1 |
2008-03-14 | A possible mechanism of ultrafast amorphization in phase-change memory alloys: an ion slingshot from the crystalline to amorphous position | We propose that the driving force of an ultrafast crystalline-to-amorphous
transition in phase-change memory alloys are strained bonds existing in the
(metastable) crystalline phase. For the prototypical example of GST, we
demonstrate that upon breaking of long Ge-Te bond by photoexcitation Ge ion
shot from an octahedr... | 0803.2127v1 |
2008-03-24 | Theoretical study of the intrinsic magnetic properties of disordered $Fe_{1-x}Ru_x$ alloys: a mean-field approach | The magnetic properties of the $Fe_{1-x}Ru_x$ alloy system for 0 $\leq$ x
$\leq$ 0.10 are studied by using a mean-field approximation based on the
Bogoliubov inequality. Ferromagnetic Fe-Fe spin correlations and
antiferromagnetic Fe-Ru and Ru-Ru exchanges have been considered to describe
the temperature dependence of t... | 0803.3439v1 |
2008-04-02 | First-principles study of the optical properties of MgxTi(1-x)H2 | The optical and electronic properties of Mg-Ti hydrides are studied using
first-principles density functional theory. Dielectric functions are calculated
for MgxTi(1-x)H2 with compositions x = 0.5, 0.75, and 0.875. The structure is
that of fluorite TiH2 where both Mg and Ti atoms reside at the Ti positions of
the latti... | 0804.0376v1 |
2008-04-08 | Phase diagram of Fe-doped Ni-Mn-Ga ferromagnetic shape-memory alloys | We have studied the effect of Fe addition on the structural and magnetic
transitions in the magnetic shape memory alloy Ni-Mn-Ga by substituting
systematically each atomic species by Fe. Calorimetric and AC susceptibility
measurements have been carried out in order to study the magnetic and
structural transformation pr... | 0804.1236v1 |
2008-04-11 | Dissipative structure formation during crystallization of alloys under high-nonequilibrium conditions | The crystallization of a binary system is investigated in computer model
which takes into account a temperature dependence of diffusion coefficient and
a nonequilibrium partition of dissolved component of the alloy. The dependence
of interface velocity on an undercooling at the dendrite tip is obtained during
rapid sol... | 0804.1868v1 |
2008-05-22 | Repeated magnetic compensation behaviour in Nd0.75Gd0.25Rh3B2 alloy having hexagonal structure and planar anisotropy | The results of dc and ac magnetization, electrical resistance and heat
capacity studies in an admixed rare earth alloy Nd0.75Gd0.25Rh3B2, which is
close to the zero magnetization limit, are reported. Novel observations include
the two antiferromagnetic like transitions, concomitant repeated/multiple
magnetic compensati... | 0805.3412v2 |
2008-06-02 | Competition between Kondo and RKKY exchange couplings in Pu{1-x}Am{x} alloys | To clarify the role of the Kondo effect in screening local magnetic moments
of Plutonium 5f--electrons as well as its competition to the RKKY interactions
we use a combination of density functional theory with static Hartree Fock and
dynamic Hubbard 1 approximations to calculate the strength of both the Kondo
exchange,... | 0806.0408v1 |
2008-06-03 | Enhanced superconductivity in Hf-base metallic glasses | Systematic study of electrical resistivity of Hf_{100-x}Fe_x (x=20,25),
Hf_{100-x}Cu_x (x=30,40,50), and Ti_{65}Cu_{35} metallic glasses has been done
in the temperature range 0.3 K - 290 K, and in magnetic fields B <= 5 T. All
Hf-base alloys are superconducting with T_c >= 0.44 K, which is well above T_c
of pure cryst... | 0806.0515v2 |
2008-06-23 | Ab-initio Study on the Magnetic Structures in the Ordered Mn3Pt Alloy | We study the electronic states of the magnetically ordered Mn3Pt alloy within
the density functional theory. Mn3Pt has been believed that one third of Mn
atoms have no magnetic moment in an antiferromagnetic phase (so-called the
F-phase) realized in the temperature range of 400 K < T < 475 K. We show that
this experime... | 0806.3627v1 |
2008-06-29 | On the insights into phases of liquid water from study of its unusual glass-forming properties | We investigate whether an interpretation of water's thermodynamics [Science,
319, 582 (2008)] by using analogy with the binary metal alloys lambda-type
ordering transition or buckminsterfullerene's orientational-ordering transition
has merit. On examining the heat capacity data used for the nanoconfined water,
the cons... | 0806.4775v1 |
2008-07-10 | Experimental Investigation of Thickness Effects on Mixed-mode I/II Fracture of an Aluminum Alloy | Experimental investigations on the effect of thicknesses on mixed-mode I/II
fracture are performed with an aluminum alloy with thicknesses of 2, 4, 8 and
14 mm. It is found that under pure-mode I loading condition, the loading
capacity per unit thickness monotonically decreases with increasing thickness.
However, under... | 0807.1577v2 |
2008-09-12 | Spin-Diffusion Lengths in Dilute Cu(Ge) and Ag(Sn) Alloys | We use current-perpendicular-to-plane (CPP) exchange-biased spin-valves to
directly measure spin diffusion lengths lsf for N = Cu(2.1 at.%Ge) and Ag(3.6
at.%Sn) alloys. We find lsf(Cu2%Ge)) = 117+10-6 nm and lsf(Ag4%Sn)= 39 +/- 3
nm. The good agreement of this lsf(Cu2%Ge) with the value lsf(Cu2%Ge) = 121 +/-
10 nm deri... | 0809.2250v1 |
2008-10-13 | Tunable Hydrogen Storage in Magnesium - Transition Metal Compounds | Magnesium dihydride ($\mgh$) stores 7.7 weight % hydrogen, but it suffers
from a high thermodynamic stability and slow (de)hydrogenation kinetics.
Alloying Mg with lightweight transition metals (TM = Sc, Ti, V, Cr) aims at
improving the thermodynamic and kinetic properties. We study the structure and
stability of Mg$_x... | 0810.2254v1 |
2008-11-08 | Spin-orbit strength driven crossover between intrinsic and extrinsic mechanisms of the anomalous Hall effect in epitaxial L1o FePd and FePt | We determine the composition of intrinsic as well as extrinsic contributions
to the anomalous Hall effect (AHE) in the isoelectronic L1o FePd and FePt
alloys. We show that the AHE signal in our 30 nm thick epitaxially deposited
films of FePd is mainly due to extrinsic side-jump, while in the epitaxial FePt
films of the... | 0811.1258v3 |
2008-12-04 | Exchange bias and its phase reversal in the zero magnetization admixed rare earth intermetallics | Exchange bias effect is an important attribute in several device
applications. Traditionally, it is discussed as a form of exchange anisotropy
at the interface between the ferromagnetic/antiferromagnetic layers of two
distinct systems. We report here on the magnetically ordered alloys possessing
the feature of unidirec... | 0812.0929v1 |
2009-02-03 | Model for the on-site matrix elements of the tight-binding hamiltonian of a strained crystal: Application to silicon, germanium and their alloys | We discuss a model for the on-site matrix elements of the sp3d5s*
tight-binding hamiltonian of a strained diamond or zinc-blende crystal or
nanostructure. This model features on-site, off-diagonal couplings between the
s, p and d orbitals, and is able to reproduce the effects of arbitrary strains
on the band energies a... | 0902.0491v1 |
2009-02-12 | Investigation of Sb diffusion in amorphous silicon | Amorphous silicon materials and its alloys become extensively used in some
technical applications involving large area of the microelectronic and
optoelectronic devices. However, the amorphous-crystalline transition,
segregation and diffusion processes still have numerous unanswered questions.
In this work we study the... | 0902.2042v1 |
2009-03-12 | Lifshitz Tails for Generalized Alloy Type Random Schrödinger Operators | We study Lifshitz tails for random Schr\"odinger operators where the random
potential is alloy type in the sense that the single site potentials are
independent, identically distributed, but they may have various function forms.
We suppose the single site potentials are distributed in a finite set of
functions, and we ... | 0903.2105v2 |
2009-05-02 | Further Comments on the replies given by Yoshihiko Yokoyama and Akihisa Inoue (Mater. Trans. 50 (2009) 2504-2506.) for Tsuyoshi Kajitani (Mater. Trans. 50 (2009) 2502-2503.) | Yokoyama and Inoue gabe their replies to eight questions raised by the
present author with respect to their paper on "Production of Zr55Cu30Ni5Al10
glassy alloy rod of 30mm in diameter by a cap-cast technique" in 2007. Yokoyama
and Inoue stressed in their reply that there were no inadequeate descriptions
in their paper... | 0905.0172v2 |
2009-05-14 | Transformation kinetics of alloys under non-isothermal conditions | The overall solid-to-solid phase transformation kinetics under non-isothermal
conditions has been modeled by means of a differential equation method. The
method requires provisions for expressions of the fraction of the transformed
phase in equilibrium condition and the relaxation time for transition as
functions of te... | 0905.2276v1 |
2009-05-25 | Si-induced superconductivity and structural transformations in DyRh4B4 | DyRh4B4 has been known to crystallize in the primitive tetragonal
(pt)-structure and to exhibit a ferromagnetic transition at 12 K, the highest
magnetic transition temperature in the entire series of the RRh4B4 materials
[1]. We show here that our silicon-added samples of the nominal composition
DyRh4B4Si0.2 exhibit su... | 0905.4032v1 |
2009-06-04 | Sensitivity of Ag/Al Interface Specific Resistances to Interfacial Intermixing | We have measured an Ag/Al interface specific resistance, 2AR(Ag/Al)(111) =
1.4 fOhm-m^2, that is twice that predicted for a perfect interface, 50% larger
than for a 2 ML 50%-50% alloy, and even larger than our newly predicted 1.3
fOhmm^2 for a 4 ML 50%-50% alloy. Such a large value of 2ARAg/Al(111) confirms
a predicted... | 0906.0934v1 |
2009-06-29 | Adaptive modulations of martensites | Modulated phases occur in numerous functional materials like giant
ferroelectrics and magnetic shape memory alloys. To understand the origin of
these phases, we review and generalize the concept of adaptive martensite. As a
starting point, we investigate the coexistence of austenite, adaptive 14M phase
and tetragonal m... | 0906.5365v1 |
2009-07-29 | Hafnium binary alloys from experiments and first principles | Despite the increasing importance of hafnium in numerous technological
applications, experimental and computational data on its binary alloys is
sparse. In particular, data is scant on those binary systems believed to be
phase separating. We performed a comprehensive study of 44 hafnium binary
systems with alkali metal... | 0907.5131v1 |
2009-08-31 | Lorentz microscopy mapping for domain walls structure study in L1$_0$ FePd thin films | Thin film alloys with perpendicular anisotropy were studied using Lorentz
Transmission Electron Microscopy (LTEM). This work focuses on the configuration
of domain walls and demonstrates the suitability and accuracy of LTEM for the
magnetic characterisation of perpendicular magnetic anisotropy materials. Thin
films of ... | 0908.4463v1 |
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