publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2010-11-03 | Element specific characterization of heterogeneous magnetism in (Ga,Fe)N films | We employ x-ray spectroscopy to characterize the distribution and magnetism
of particular alloy constituents in (Ga,Fe)N films grown by metal organic vapor
phase epitaxy. Furthermore, photoelectron microscopy gives direct evidence for
the aggregation of Fe ions, leading to the formation of Fe-rich nanoregions
adjacent ... | 1011.0847v1 |
2010-11-10 | Tuning macro-twinned domain sizes and the b-variants content of the adaptive 14-modulated martensite in epitaxial Ni-Mn-Ga films by co-sputtering | In order to obtain modulated-martensite in our epitaxial Ni-Mn-Ga films, we
have tuned the composition by using a co-sputtering process. Here we present
how the composition affects the variant distribution of the 14-modulated
martensite at room temperature. The nature of such modulated-martensites is
still strongly deb... | 1011.2303v1 |
2010-11-17 | Striped periodic minimizers of a two-dimensional model for martensitic phase transitions | In this paper we consider a simplified two-dimensional scalar model for the
formation of mesoscopic domain patterns in martensitic shape-memory alloys at
the interface between a region occupied by the parent (austenite) phase and a
region occupied by the product (martensite) phase, which can occur in two
variants (twin... | 1011.3935v1 |
2010-11-18 | Simulation of structural phase transitions in NiTi | By means of molecular-dynamics simulations, temperature driven diffusionless
structural phase transitions in equi- and nearly equiatomic ordered
nickel-titanium alloys were investigated. For this purpose, a model potential
from the literature was adopted [W.S. Lai and B.X. Liu, J. Phys. Condens.
Matter 12, L53 (2000)],... | 1011.4279v1 |
2010-11-22 | Atomistic theory of spin relaxation in self-assembled In$_{1-x}$Ga$_x$As/GaAs quantum dots at zero magnetic field | We present full atomistic calculations of the spin-flip time (T$_{1}$) of
electrons and holes mediated by acoustic phonons in self-assembled
In$_{1-x}$Ga$_x$As/GaAs quantum dots at zero magnetic field. At low magnetic
field, the first-order process is suppressed, and the second-order process
becomes dominant. We find t... | 1011.4724v1 |
2010-12-06 | Room temperature ferromagnetism and anomalous Hall effect in Si$_{1-x}$Mn$_x$ ($x\approx 0.35$) alloys | A detailed study of the magnetic and transport properties of Si$_{1-x}$Mn$_x$
($x\approx 0.35$) films is presented. We observe the anomalous Hall effect
(AHE) in these films up to room temperature. The results of the magnetic
measurements and the AHE data are consistent and demonstrate the existence of
long-range ferro... | 1012.1172v1 |
2010-12-17 | First-principles study of phase stability of Gd-doped EuO and EuS | Phase diagrams of isoelectronic Eu$_{1-x}$Gd$_x$O and Eu$_{1-x}$Gd$_{x}$S
quasi-binary alloy systems are constructed using first-principles calculations
combined with the standard cluster expansion approach and Monte-Carlo
simulations. The oxide system has a wide miscibility gap on the Gd-rich side
but forms ordered co... | 1012.4026v1 |
2010-12-22 | Pressure-induced phase transition of Bi2Te3 into the bcc structure | The pressure-induced phase transition of bismuth telluride, Bi2Te3, has been
studied by synchrotron x-ray diffraction measurements at room temperature using
a diamond-anvil cell (DAC) with loading pressures up to 29.8 GPa. We found a
high-pressure body-centered cubic (bcc) phase in Bi2Te3 at 25.2 GPa, which is
denoted ... | 1012.4932v1 |
2011-01-11 | Possible Coexistence of Superconductivity and Magnetism in Intermetallic NiBi3 | NiBi3 polycrystals were synthesized via a solid state method. X-ray
diffraction analysis shows that the main phase present in the sample
corresponds to NiBi3 in a weight fraction of 96.82 % according to the
refinement of the crystalline structure. SEM - EDS and XPS analysis reveal a
homogeneous composition of NiBi3, wi... | 1101.2226v1 |
2011-01-19 | Mechanisms of Stranski-Krastanov Growth | Stranski-Krastanov (SK) growth is reported experimentally as the growth mode
that is responsible for the transition to three dimensional islands in
heteroepitaxial growth. A kinetic Monte Carlo (KMC) model is proposed that can
replicate many of the experimentally observed features of this growth mode.
Simulations revea... | 1101.3775v4 |
2011-01-20 | Preparation and characterization of magnesium coating deposited by cold spraying | Magnesium (Mg) and its alloys have a great potential as structural materials
due to their beneficial combination of high strength to weight ratio, high
thermal conductivity and good machinability. However, few literatures about Mg
coatings fabricated by cold spraying can be found. In this study, Mg coatings
were fabric... | 1101.4031v1 |
2011-01-25 | Anderson Localization Triggered by Spin Disorder---with an Application to Eu_x Ca_1-x B_6 | The phenomenon of Anderson localization is studied for a class of
one-particle Schr\"odinger operators with random Zeeman interactions. These
operators arise as follows: Static spins are placed randomly on the sites of a
simple cubic lattice according to a site percolation process with density x and
coupled to one anot... | 1101.4852v1 |
2011-01-25 | Ultra-large tensile strains and martensite destabilization observed in high-temperature Ni57.5Mn22.5Ga20.0 single crystal | Tensile stress-strain behavior of Ni57.5Mn22.5Ga20.0 single crystal
exhibiting a high-temperature 2M-martensitic phase stable up to 360\degree C
has been studied in the course of thermal and mechanical cycling. The
ultra-large reversible strains, about 9%, caused by the shape memory and
superelasticity effects, have be... | 1101.4866v1 |
2011-01-28 | Evidence for electron-phonon interaction in Fe$_{1-x}$M$_{x}$Sb$_{2}$ (M=Co, Cr) single crystals | We have measured polarized Raman scattering spectra of the
Fe$_{1-x}$Co$_{x}$Sb$_{2}$ and Fe$_{1-x}$Cr$_{x}$Sb$_{2}$ (0$\leq x\leq $0.5)
single crystals in the temperature range between 15 K and 300 K. The highest
energy $B_{1g}$ symmetry mode shows significant line asymmetry due to phonon
mode coupling width electroni... | 1101.5511v1 |
2011-02-02 | Transparent yttrium hydride thin films prepared by reactive sputtering | Metal hydrides have earlier been suggested for utilization in solar cells.
With this as a motivation we have prepared thin films of yttrium hydride by
reactive magnetron sputter deposition. The resulting films are metallic for low
partial pressure of hydrogen during the deposition, and black or
yellow-transparent for h... | 1102.0450v2 |
2011-02-21 | Extrinsic Spin Hall Effect Induced by Iridium Impurities in Copper | We study the extrinsic spin Hall effect induced by Ir impurities in Cu by
injecting a pure spin current into a CuIr wire from a lateral spin valve
structure. While no spin Hall effect is observed without Ir impurity, the spin
Hall resistivity of CuIr increases linearly with the impurity concentration.
The spin Hall ang... | 1102.4116v2 |
2011-02-21 | Contributions of Al and Ni segregation to the interfacial cohesion of Cu-rich precipitates in ferritic steels | We characterise the influence of the segregation behaviours of two typical
alloying elements, aluminium and nickel, on the interfacial cohesive properties
of copper-rich precipitates in ferritic steels, with a view towards
understanding steel embrittlement. The first-principles method is used to
compute the energetic a... | 1102.4234v2 |
2011-02-22 | Strain balanced quantum posts | Quantum posts are assembled by epitaxial growth of closely spaced quantum dot
layers, modulating the composition of a semiconductor alloy, typically InGaAs.
In contrast with most self-assembled nanostructures, the height of quantum
posts can be controlled with nanometer precision, up to a maximum value limited
by the a... | 1102.4490v3 |
2011-03-01 | Structural, magnetic and thermal properties of the substitution series Ce$_2$(Pd$_{1-x}$Ni$_x$)$_2$Sn | Structural, magnetization and heat capacity studies were performed on
Ce$_2$(Pd$_{1-x}$Ni$_x$)$_2$Sn ($0 \leq x \leq 1$) alloys. The substitution of
Pd atoms by isoelectronic Ni leads to a change in the crystallographic
structure from tetragonal (for $x \leq 0.3$) to centered orthorhombic lattice
(for $x \geq 0.4$). Th... | 1103.0190v1 |
2011-03-02 | Anomalous Hall effect in NiPt thin films | We study Hall effect in sputtered NixPt1-x thin films with different Ni
concentrations. Temperature, magnetic field and angular dependencies are
analyzed and the phase diagram of NiPt thin films is obtained. It is found that
films with sub-critical Ni concentration exhibit cluster-glass behavior at low
temperatures wit... | 1103.0367v2 |
2011-03-22 | Study of phase stability in the $σ$-FeCr system | Formation energy of the $\sigma$-phase in the Fe-Cr alloy system, $\Delta E$,
was computed versus the occupancy changes on each of the five possible lattice
sites. Its dependence on a number of Fe-atoms per unit cell, $N_{Fe}$, was
either monotonically increasing or decreasing function of $N_{Fe}$, depending
on the sit... | 1103.4260v1 |
2011-03-22 | Absence of boron aggregates in superconducting silicon confirmed by atom probe tomography | Superconducting boron-doped silicon films prepared by gas immersion laser
doping (GILD) technique are analyzed by atom probe tomography. The resulting
three-dimensional chemical composition reveals that boron atoms are
incorporated into crystalline silicon in the atomic percent concentration
range, well above their sol... | 1103.4409v2 |
2011-03-28 | Composition-tuned smeared phase transitions | Phase transitions in random systems are smeared if individual spatial regions
can order independently of the bulk system. In this paper, we study such
smeared phase transitions (both classical and quantum) in substitutional alloys
A$_{1-x}$B$_x$ that can be tuned from an ordered phase at composition $x=0$ to
a disorder... | 1103.5439v2 |
2011-04-11 | Synthesis and study of alpha-Fe1.4Ga0.6O3: An advanced Ferromagnetic Semiconductor | We report the synthesis of alpha-Fe1.4Ga0.6O3 compound and present its
structural phase stability and interesting magnetic, dielectric and
photo-absorption properties. In our work Ga doped alpha-Fe2O3 samples are well
stabilized in alpha phase (rhombohedral crystal structure with space group
R3C). Properties of the pre... | 1104.1982v1 |
2011-05-05 | New pressure-induced monoclinic β-Sb2Te3 phase with sevenfold symmetry | A nanometric Sb2Te3 rhombohedral phase was produced from Sb and Te by
mechanical alloying for 3 hours and its structural stability was studied by
synchrotron X-ray diffraction (XRD) and Raman spectroscopy (RS) measurements as
a function of pressure. A phase transformation from the ambient pressure
rhombohedral phase in... | 1105.1097v1 |
2011-05-14 | Fluorescence lifetime modification in Eu:Lu2O3 nanoparticles in the presence of silver nanoparticles | Europium-doped lutetium-oxide (Eu:Lu2O3) nanoparticles were synthesized using
a combustion technique and a co-precipitation technique, and their properties
were compared. Surface-modification utilizing small silane molecules and long
chain polymers were explored to de-agglomerate and disperse the particles.
Structural,... | 1105.2910v1 |
2011-05-18 | Ordered Semiconducting Nitrogen-Graphene Alloys | The interaction between substitutional nitrogen atoms in graphene is studied
by performing first principles calculations. The nearest neighbor interaction
between nitrogen dopants is highly repulsive because of the strong
electrostatic repulsion between nitrogen atoms, which prevents the full phase
separation in nitrog... | 1105.3540v2 |
2011-05-24 | Efficient Isoparametric Integration over Arbitrary, Space-Filling Voronoi Polyhedra for Electronic-Structure Calculations | A numerically efficient, accurate, and easily implemented integration scheme
over convex Voronoi polyhedra (VP) is presented for use in {\it ab-initio}
electronic-structure calculations. We combine a weighted Voronoi tessellation
with isoparametric integration via Gauss-Legendre quadratures to provide
rapidly convergen... | 1105.4888v1 |
2011-06-01 | The ground state phase diagram of the diluted ferromagnetic Kondo-lattice model | We investigate the existence of several (anti-)ferromagnetic phases in the
diluted ferromagnetic Kondo-lattice model, i.e. ferromagnetic coupling of local
moment and electron spin. To do this we use a coherent potential approximation
(CPA) with a dynamical alloy analogy. For the CPA we need effective potentials,
which ... | 1106.0181v1 |
2011-06-09 | Simple metal binary phases based on the body centered cubic structure: electronic origin of distortions and superlattices | Binary alloy phases of the noble metals with main group elements are analyzed
in relation to body centered cubic structure with orthorhombic and hexagonal
distortions. Stability of these distorted phases is considered on the base of
the Fermi sphere - Brillouin zone interaction to understand the important part
of the b... | 1106.1725v1 |
2011-06-19 | Anomalous slow dynamics in the metallic helimagnet Gd_{1-x}Y_{x} | Ac-suseptibility measurements were performed in the metallic helimagnet
Gd_{1-x}Y_{x} alloy. A remarkable increase of the imaginary part of the
ac-suseptibility was observed in the temperature range of the helimagnetic
phase. Moreover, a strong nonlinearity of the magnetization was observed at
paramagnetic-helimagnetic... | 1106.3730v1 |
2011-06-23 | Enhancement of magnetism of Fe by Cr and V | Enhancement of magnetism of Fe that occurs by alloying with Cr or V is
discussed on the basis of first-principles electronic structure calculation.
The d states of Fe next to Cr(V) are pushed down to the lower energy side
compared to those of pure Fe due to the hybridization with Cr(V) d states,
which leads a Co-like e... | 1106.4630v1 |
2011-06-27 | Effect of intraband Coulomb repulsion on the excitonic spin-density wave | We present a study of the magnetic ground state of a two-band model with
nested electron and hole Fermi surfaces and both interband and intraband
Coulomb interactions. Our aim is to understand how the excitonic
spin-density-wave (ESDW) state induced by the interband Coulomb repulsion is
affected by the intraband intera... | 1106.5315v2 |
2011-07-08 | Mathematical modeling of magnetostrictive nanowires for sensor application | Magnetostrictive wires of diameter in the nanometer scale have been proposed
for application as acoustic sensors [Downey et al., 2008], [Yang et al., 2006].
The sensing mechanism is expected to operate in the bending regime. In this
work we derive a variational theory for the bending of magnetostrictive
nanowires start... | 1107.1729v2 |
2011-07-11 | New Indivisible Geoscience Paradigm | Earth's interior, I posit, is like one of the rare, oxygen-starved "enstatite
chondrite" meteorites (and unlike a more-oxidized "ordinary chondrite" as has
been believed for seventy years). Laboratory-analyzed enstatite-chondrite
samples are comparable to having-in-hand impossibleto- gather deep-Earth
samples. Enstatit... | 1107.2149v1 |
2011-07-13 | Electron spin resonance study of the LaIn3-xSnx superconducting system | The LaIn3-xSnx alloy system is composed of superconducting Pauli paramagnets.
For LaIn3 the superconducting critical temperature T_c is approximately 0.7 K
and it shows an oscillatory dependence as a function of Sn substitution,
presenting its highest value T_c ~ 6.4 K for the LaSn3 end member. The
superconducting stat... | 1107.2587v2 |
2011-07-13 | Technique for high axial shielding factor performance of large-scale, thin, open-ended, cylindrical Metglas magnetic shields | Metglas 2705M is a low-cost commercially-available, high-permeability
Cobalt-based magnetic alloy, provided as a 5.08-cm wide and 20.3-$\mu$m thick
ribbon foil. We present an optimized construction technique for single-shell,
large-scale (human-size), thin, open-ended cylindrical Metglas magnetic
shields. The measured ... | 1107.2625v1 |
2011-07-19 | Magnetic nanostructures by adaptive twinning in strained epitaxial films | We exploit the intrinsic structural instability of the Fe70Pd30 magnetic
shape memory alloy to obtain functional epitaxial films exhibiting a
self-organized nanostructure. We demonstrate that coherent epitaxial straining
by 54% is possible. The combination of thin film experiments and large-scale
first-principles calcu... | 1107.3763v3 |
2011-07-22 | First-principles calculations of $^{17}$O NMR chemical shielding in Pb(Zr$_{1/2}$Ti$_{1/2}$)O$_3$ and Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_3$: linear dependence on transition-metal/oxygen bond lengths | First-principles density functional theory (DFT) oxygen chemical shift
tensors were calculated for A(B,B$^{\prime}$)O$_3$ perovskite alloys
Pb(Zr$_{1/2}$Ti$_{1/2}$)O$_3$ (PZT) and Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_3$ (PMN).
Quantum chemistry methods for embedded clusters and the GIPAW method [C.\ J.\
Pickard and F.\ Mauri, {\... | 1107.4611v1 |
2011-07-31 | Atypical thermodynamic behavior of Ce compounds in the vicinity of zero temperature Critical Points | A systematic analysis of thermodynamic properties performed on Ce-base
exemplary compounds allows to identify different types of behaviors as the
system approaches the quantum critical region. They are recognized in the
respective magnetic phase boundaries (T_{N,C}(x)) as a change from the
classical negative curvature ... | 1108.0197v1 |
2011-08-01 | Spin Pumping and Spin Transfer | Spin pumping is the emission of a spin current by a magnetization dynamics
while spin transfer stands for the excitation of magnetization by spin
currents. Using Onsager's reciprocity relations we prove that spin pumping and
spin-transfer torques are two fundamentally equivalent dynamic processes in
magnetic structures... | 1108.0385v3 |
2011-08-03 | Planar hybrid superconductor-normal metal-superconductor thin film junctions based on BaFe1.8Co0.2As2 | To investigate the transport properties of iron based superconductors, we
prepared planar hybrid superconductor-normal metal-superconductor (SNS') thin
film junctions with BaFe1.8Co0.2As2 as base electrode. As counter electrode we
used a lead indium alloy, while the normal metal layer was formed by thin gold
films. Tem... | 1108.0851v2 |
2011-08-08 | Anisotropy effects on Rashba and topological insulator spin polarized surface states: a unified phenomenological description | Spin polarized two-dimensional electronic states have been previously
observed on metallic surface alloys with giant Rashba splitting and on the
surface of topological insulators. We study the surface band structure of these
systems, in a unified manner, by exploiting recent results of k.p theory. The
model suggests a ... | 1108.1778v3 |
2011-08-13 | Effect of Piezoelectric Polarization on Phonon group velocity in Wurtzite Nitrides | We have investigated the effect of piezoelectric (PZ) polarization property
on group velocity of phonons in binary as well as in ternary wurtzite nitrides.
It is found that with the presence of PZ polarization property, the phonon
group velocity is modified. The change in phonon group velocity due to PZ
polarization ef... | 1108.2770v2 |
2011-08-16 | Thermoelectric prospects of nanomaterials with spin-orbit surface bands | Nanostructured composites and nanowire arrays of traditional thermoelectrics
like Bi, Bi(1-x)Sb(x) and Bi(2)Te(3) have metallic Rashba surface spin-orbit
bands featuring high mobilities rivaling that of the bulk for which topological
insulator behavior has been proposed. Nearly pure surface electronic transport
has bee... | 1108.3356v1 |
2011-08-19 | Second-phase nucleation on an edge dislocation | A model for nucleation of second phase at or around dislocation in a
crystalline solid is considered. The model employs the Ginzburg-Landau theory
of phase transition comprising the sextic term in order parameter in the Landau
free energy. The ground state solution of the linearized time-independent
Ginzburg-Landau equ... | 1108.3935v1 |
2011-08-30 | Ab Initio Theory of Scattering-Independent Anomalous Hall Effect | We report on first-principles calculations of the side-jump contribution to
the anomalous Hall conductivity (AHC) directly from the electronic structure of
a perfect crystal. We implemented our approach for a short-range scattering
disorder model within the density functional theory and computed the full
scattering-ind... | 1108.5917v1 |
2011-08-30 | Reducing Disorder in Artificial Kagome Ice | Artificial spin ice has become a valuable tool for understanding magnetic
interactions on a microscopic level. The strength in the approach lies in the
ability of a synthetic array of nanoscale magnets to mimic crystalline
materials, composed of atomic magnetic moments. Unfortunately, these nanoscale
magnets, patterned... | 1108.6071v1 |
2011-08-31 | The role of lighter and heavier embedded nanoparticles on the thermal conductivity of SiGe alloys | We have used an atomistic {\it ab initio} approach with no adjustable
parameters to compute the lattice thermal conductivity of Si$_{0.5}$Ge$_{0.5}$
with a low concentration of embedded Si or Ge nanoparticles of diameters up to
4.4 nm. Through exact Green's function calculation of the nanoparticle
scattering rates, we ... | 1108.6137v1 |
2011-08-31 | Area-dependence of spin-triplet supercurrent in ferromagnetic Josephson junctions | In 2010, several experimental groups obtained compelling evidence for
spin-triplet supercurrent in Josephson junctions containing strong
ferromagnetic materials. Our own best results were obtained from large-area
junctions containing a thick central Co/Ru/Co "synthetic antiferromagnet" and
two thin outer layers made of... | 1108.6243v1 |
2011-09-17 | Monte Carlo simulations in a disordered binary Ising model | In this work we study a disordered binary Ising model on the square lattice.
The model system consists of two different particles with spin-1/2 and spin-1,
which are randomly distributed on the lattice. It has been considered only spin
nearest-neighbor exchange interactions with $J>0$. This system can represent a
disor... | 1109.3797v1 |
2011-09-19 | Magnetic nanocomposites: new methodology for micromagnetic modeling and SANS experiments | A new methodology for micromagnetic simulations of magnetic nanocomposites is
presented. The methodology is especially suitable for simulations of two-phase
composites consisting of magnetically hard inclusions in a soft magnetic matrix
phase. The proposed technique allows to avoid the unnecessary discretization of
the... | 1109.4075v1 |
2011-09-22 | Self-Diffusion of Iron in L10 FePd film - as revealed by reflectometric methods | L10 (CuAu(I)-type) ordered FePd as well as FePt and CoPt, due to their high
magnetic anisotropy, are candidate materials for future ultra-high density
magnetic recording. Atomic diffusion governs the structural relaxation and
associated changes in the physical and magnetic properties in these alloys.
Such processes inv... | 1109.4751v1 |
2011-09-27 | Coexistence of quantum-confined Stark effect and localized states in an (In,Ga)N/GaN nanowire heterostructure | We analyze the emission of single GaN nanowires with (In,Ga)N insertions
using both micro-photoluminescence and cathodoluminescence spectroscopy. The
emission spectra are dominated by a green luminescence band that is strongly
blueshifted with increasing excitation density. In conjunction with
finite-element simulation... | 1109.6039v1 |
2011-10-04 | Transition metal impurity effect on charge and spin density in iron: Ab initio calculations and comparison with Mössbauer data | Density functional theory was applied to study influence of the isolated
impurity located on the regular site of the alpha-Fe crystal on the charge and
spin density (hyperfine interactions) on the iron nucleus. Calculations were
performed by using both pseudopotential and the full potential methods. The
scalar relativi... | 1110.0717v1 |
2011-10-06 | Nucleation of second-phase near elastic defects in crystalline solids | The problem of heterogeneous nucleation of second-phase in alloys in the
vicinity of elastic defects is considered. The defect can be a dislocation line
or a crack tip residing in a crystalline solid. We use the Ginzburg-Landau
equation to describe the spatiotemporal evolution of the order parameter in the
environs of ... | 1110.1292v1 |
2011-10-10 | Microscopic origins of the anomalous melting behaviour of high-pressure sodium | Recent experiments have shown that sodium, a prototype simple metal at
ambient conditions, exhibits unexpected complexity under high pressure. One of
the most puzzling phenomena in the behaviour of dense sodium is the
pressure-induced drop in its melting temperature, which extends from 1000 K at
~30GPa to as low as roo... | 1110.2031v1 |
2011-10-12 | Origin of perpendicular anisotropy in thin Co/Pt bilayers grown on alumina | We investigate in this paper the origin of perpendicular anisotropy in Co
(1.6 nm)/Pt (3.0 nm) bilayers grown on alumina and annealed up to
650$^{\circ}$C. Above 350$^{\circ}$C, all layers exhibit perpendicular
anisotropy. Then coercive fields increase linearly with annealing temperature
following two different rates: ... | 1110.2628v1 |
2011-10-17 | Failure of the Maxwell relation for the quantification of caloric effects in ferroic materials | Giant caloric effects were reported in elasto-, electro- and magnetocaloric
materials near phase transformations. Commonly, their entropy change is
indirectly evaluated by a Maxwell relation. We report the fundamental failure
of this approach. We analyze exemplarily the Ni-Mn-Ga magnetic shape memory
alloy. An applied ... | 1110.3617v1 |
2011-10-18 | Effects of Interface Disorder on Valley Splitting in SiGe/Si/SiGe Quantum Wells | A sharp potential barrier at the Si/SiGe interface introduces valley
splitting (VS), which lifts the 2-fold valley degeneracy in strained
SiGe/Si/SiGe quantum wells (QWs). This work examines in detail the effects of
Si/SiGe interface disorder on the VS in an atomistic tight binding approach
based on statistical samplin... | 1110.4097v2 |
2011-10-19 | Synthesis of novel rare earth - iron oxide chalcogenides with the La2Fe2O3Se2 structure | Our searches for new oxide chalcogenides of rare earths and Fe, Co, Ni, and
Zn resulted in preparation of two new compounds Ce2Fe2O3S2 and Pr2Fe2O3S2 which
are isostructural to La2Fe2O3Se2 and Sm2Ti2O3Sb2. Crystal structures of the new
compounds Ce2Fe2O3S2 and Pr2Fe2O3S2 were determined from powder X-ray
diffraction da... | 1110.4234v1 |
2011-11-03 | Physical properties of Thallium-Tellurium based thermoelectric compounds using first-principles simulations | We present a study of the thermodynamic and physical properties of Tl5Te3,
BiTl9Te6 and SbTl9Te6 compounds by means of density functional theory based
calculations. The optimized lattice constants of the compounds are in good
agreement with the experimental data. The electronic density of states and band
structures are... | 1111.0793v1 |
2011-11-07 | Prediction of Orientational Phase Transition in Boron Carbide | The assessed binary phase diagram of boron-carbon exhibits a single alloy
phase designated "B4C" with rhombohedral symmetry occupying a broad composition
range that falls just short of the nominal carbon content of 20%. As this
composition range is nearly temperature independent, the phase diagram suggests
a violation ... | 1111.1737v1 |
2011-11-08 | Calculations of excess free energies of precipitates via direct thermodynamic integration across phase boundaries | We describe a technique for constraining macroscopic fluctuations in
thermodynamic variables well-suited for Monte Carlo (MC) simulations of
multiphase equilibria. In particular for multicomponent systems this amounts to
a statistical ensemble that implements constraints on both the average
composition as well as its f... | 1111.1880v3 |
2011-11-18 | Enhanced refrigerant capacity and magnetic entropy flattening using a two-amorphous FeZrB(Cu) composite | The temperature dependence of the isothermal magnetic entropy change,
{\Delta}SM, and the magnetic field dependence of the refrigerant capacity, RC,
have been investigated in a composite system xA+(1-x)B, based on Fe87Zr6B6Cu1
(A) and Fe90Zr8B2 (B) amorphous ribbons. Under a magnetic field change of 2 T
the maximum imp... | 1111.4340v1 |
2011-11-28 | Contrasting magnetic behavior of fine particles of some Kondo Lattices | We have investigated the magnetic behavior of ball-milled fine particles of
well-known Kondo lattices, CeAu2Si2, CePd2Si2 and CeAl2, by magnetization and
heat-capacity studies in order to understand the magnetic behavior when the
particle size is reduced. These compounds have been known to order
antiferromagnetically i... | 1111.6370v1 |
2011-12-09 | Experimental evidence for Tayler instability in a liquid metal column | In the current-driven, kink-type Tayler instability (TI) a sufficiently
strong azimuthal magnetic field becomes unstable against non-axisymmetric
perturbations. The TI has been discussed as a possible ingredient of the solar
dynamo mechanism and a source of the helical structures in cosmic jets. It is
also considered a... | 1112.2103v1 |
2011-12-10 | Suppression of Grain Boundaries in Graphene Growth on Superstructured Mn-Cu(111) Surface | As undesirable defects, grain boundaries (GBs) are widespread in epitaxial
graphene using existing growth methods on metal substrates. Employing density
functional theory calculations, we first identify that the misorientations of
carbon islands nucleated on a Cu(111) surface lead to the formation of GBs as
the islands... | 1112.2283v1 |
2011-12-16 | Ab-initio tiling and atomic structure for decagonal ZnMgDy quasicrystal | We discover the detailed atomic structure of $d$-MgZnY, a stable decagonal
quasicrystal alloy of the layered Frank-Kasper type, and related phases, using
the "tiling and decoration" approach. The atoms have invariable sites in the
rectangle and triangle tiles of a 10-fold-symmetric planar tiling. To discover
the lowest... | 1112.3951v1 |
2011-12-22 | Ethylene glycol-mediated synthesis of nanoporous anatase TiO2 rods and rutile TiO2 self-assembly chrysanthemums | Nanoporous anatase TiO2 rods and rutile TiO2 chrysanthemums were successfully
synthesized via a simple ethylene glycol-mediated synthesis route. Their
morphologies, phase compositions and components were characterized by SEM, TEM,
Raman and IR, respectively. The results show that a self-assembly growth takes
place in t... | 1112.5231v2 |
2011-12-22 | Single crystal growth of YbRh2Si2 and YbIr2Si2 | We report on the single crystal growth of the heavy-fermion compounds
YbRh2Si2 and YbIr2Si2 using a high-temperature indium-flux technique. The
optimization of the initial composition and the temperature-time profile lead
to large (up to 100 mg) and clean (\rho_0=0.5 \mu\Omega cm) single crystals of
YbRh2Si2. Low-tempe... | 1112.5251v1 |
2012-01-02 | Single-ion Kondo Scaling of the Coherent Fermi Liquid Regime in Ce1-xLaxNi2Ge2 | Thermodynamic and transport properties of the La-diluted Kondo lattice
CeNi2Ge2 were studied in a wide temperature range. The Ce-rich alloys
Ce1-xLaxNi2Ge2 were found to exhibit distinct features of the coherent heavy
Fermi liquid. At intermediate compositions (0.7 <= x <= 0.9) non-Fermi liquid
properties have been obs... | 1201.0456v1 |
2012-01-10 | Spatially controlled formation of superparamagnetic (Mn,Ga)As nanocrystals in high temperature annealed (Ga,Mn)As/GaAs superlattices | The annealing-induced formation of (Mn,Ga)As nanocrystals in (Ga,Mn)As/GaAs
superlattices was studied by X-ray diffraction, transmission electron
microscopy and magnetometry. The superlattice structures with 50 A thick
(Ga,Mn)As layers separated by 25, 50 and 100 A thick GaAs spacers were grown by
molecular beam epitax... | 1201.2166v2 |
2012-01-11 | Localisation for non-monotone Schroedinger operators | We study localisation effects of strong disorder on the spectral and
dynamical properties of (matrix and scalar) Schroedinger operators with
non-monotone random potentials, on the d-dimensional lattice. Our results
include dynamical localisation, i.e. exponentially decaying bounds on the
transition amplitude in the mea... | 1201.2211v4 |
2012-01-12 | Evaporatively driven morphological instability | Simple observations of evaporating solutions reveal a complex hierarchy of
spatio-temporal instabilities. We analyze one such instability suggested by the
qualitative observations of Du and Stone and find that it is driven by a novel
variant of the classical {\em morphological instability} in alloy
solidification. In t... | 1201.3312v1 |
2012-01-16 | Initial stage of growth of single-walled carbon nanotubes : modelling and simulations | Through a careful modeling of interactions, collisions, and the catalytic
behavior, one can obtain important information about the initial stage of
growth of single-wall carbon nanotubes (SWCNTs), where a state-of-the-art
semi-empirical Hamiltonian [Phys. Rev. B, 74, 155408 (2006)] is used to model
the interaction betw... | 1201.3330v1 |
2012-01-18 | Space Charge Influence on the Angle of Conical Spikes Developing on a Liquid-Metal Anode | The influence of the space charge of ions emitted from the surface of a
conical spike on its shape has been studied. The problem of the calculation of
the spatial distributions of the electric field, ion velocity field, and the
space charge density near the cone tip has been reduced to the analysis of a
system of ordin... | 1201.3743v1 |
2012-01-20 | Laser-sintered thin films of doped SiGe nanoparticles | We present a study of the morphology and the thermoelectric properties of
short-pulse laser-sintered (LS) nanoparticle (NP) thin films, consisting of
SiGe alloy NPs or composites of Si and Ge NPs. Laser-sintering of spin-coated
NP films in vacuum results in a macroporous percolating network with a typical
thickness of ... | 1201.4370v1 |
2012-01-21 | Magneto-caloric effect in the pseudo-binary intermetallic YPrFe17 compound | We have synthesized the intermetallic YPrFe17 compound by arc-melting. X-ray
and neutron powder diffraction show that the crystal structure is rhombohedral
with View the MathML source space group (Th2Zn17-type). The investigated
compound exhibits a broad isothermal magnetic entropy change {\Delta}SM(T)
associated with ... | 1201.4411v1 |
2012-01-23 | Decoupling between Field-instabilities of Antiferromagnetism and Pseudo-metamagnetism in Rh-doped CeRu2Si2 Kondo Lattice | Doping Kondo lattice system CeRu2Si2 with Rh-8% (Ce(Ru0.92Rh0.08)2Si2) leads
to drastic consequences due to the mismatch of the lattice parameters between
CeRu2Si2 and CeRh2Si2. A large variety of experiments clarifies the unusual
properties of the ground state induced by the magnetic field from longitudinal
antiferrom... | 1201.4815v1 |
2012-01-23 | Effect of oxidation on the Mechanical Properties of Liquid Gallium and Eutectic Gallium-Indium | Liquid metals exhibit remarkable mechanical properties, in particular large
surface tension and low viscosity. However, these properties are greatly
affected by oxidation when exposed to air. We measure the viscosity, surface
tension, and contact angle of gallium (Ga) and a eutectic gallium-indium alloy
(eGaIn) while c... | 1201.4828v1 |
2012-01-24 | Monte Carlo simulations of magnetic ordering in the fcc Kagome lattice | Monte Carlo simulation results are reported on magnetic ordering in ABC
stacked Kagom\'{e} layers with fcc symmetry for both XY and Heisenberg models
which include exchange interactions with the eight near-neighbors. Well known
degeneracies of the 2D system persist in the 3D case and analysis of the
numerical data prov... | 1201.4984v1 |
2012-01-27 | The effects of Vanadium on the strength of a bcc Fe Σ3(111)[1-10] grain boundary | The effects of micro-alloying element, vanadium, on a bcc Fe \Sigma
3(111)[1-10] symmetric tilt grain boundary strength are studied using density
functional theory calculations. The lowest energy configuration of the grain
boundary structure are obtained from the first-principles calculations. The
substitutional and in... | 1201.5915v1 |
2012-01-28 | First-principles study of structural, magnetic and electronic properties of small FeRh alloy clusters | The structural, electronic and magnetic properties of small ${\rm Fe}_m {\rm
Rh}_n$ clusters having $N = m+n \leq 8$ atoms are studied in the framework of a
generalized-gradient approximation to density-functional theory. For $N = m+n
\leq 6$ a thorough sampling of all cluster topologies has been performed, while
for $... | 1201.5971v1 |
2012-02-02 | Room-Temperature Photoluminescence from Er3+ in Si-Er-O and Si-Ge-Er-O Thin Films at High Erbium Concentrations | Prior studies have shown that photoluminescence from Er3+ impurities in
silicon is severely limited at room temperature by non-radiative relaxation and
solid solubility; and room temperature emission from Er3+ in oxide-based hosts
becomes diminished at high erbium concentrations. This work presents studies of
thin film... | 1202.0574v1 |
2012-02-03 | Polarized positrons for the ILC - update on simulations | To achieve the extremely high luminosity for colliding electron-positron
beams at the future International Linear Collider (ILC) an undulator-based
source with about 230 meters helical undulator and a thin titanium-alloy target
rim rotated with tangential velocity of about 100 meters per second are
foreseen. The very h... | 1202.0752v1 |
2012-02-05 | Topological Crystalline Insulators in the SnTe Material Class | Topological crystalline insulators are new states of matter in which the
topological nature of electronic structures arises from crystal symmetries.
Here we predict the first material realization of topological crystalline
insulator in the semiconductor SnTe, by identifying its nonzero topological
index. We predict tha... | 1202.1003v2 |
2012-02-08 | Magneto-transport in a quantum network: Evidence of a mesoscopic switch | We investigate magneto-transport properties of a $\theta$ shaped three-arm
mesoscopic ring where the upper and lower sub-rings are threaded by
Aharonov-Bohm fluxes $\phi_1$ and $\phi_2$, respectively, within a
non-interacting electron picture. A discrete lattice model is used to describe
the quantum network in which tw... | 1202.1726v2 |
2012-02-11 | Coherent Potential Approximation as a Voltage Probe | Coherent potential approximation (CPA) has widely been used for studying
residual resistivity of bulk alloys and electrical conductivity in
inhomogeneous systems with structural disorder. Here we revisit the single-site
CPA within the Landauer-B\"uttiker approach applied to the electronic transport
in layered structure... | 1202.2392v1 |
2012-02-16 | Studies of material properties under irradiation at BNL Linear Isotope Producer (BLIP) | Effects of proton beams irradiating materials considered for targets in
high-power accelerator experiments have been under study using the Brookhaven
National Laboratory's (BNL) 200 MeV Linac. The primary objectives of the study
that includes a wide array of materials and alloys ranging between low and
high-Z are to (a... | 1202.3799v1 |
2012-02-17 | Radiation and thermal analysis of production solenoid for Mu2e experimental setup | The Muon-to-Electron (Mu2e) experiment at Fermilab, will seek the evidence of
direct muon to electron conversion at the sensitivity level where it cannot be
explained by the Standard Model. An 8-GeV 25-kW proton beam will be directed
onto a tilted gold target inside a large-bore superconducting Production
Solenoid (PS)... | 1202.3976v1 |
2012-02-24 | Quantum Griffiths singularities in ferromagnetic metals | We present a theory of the quantum Griffiths phases associated with the
ferromagnetic quantum phase transition in disordered metals. For Ising spin
symmetry, we study the dynamics of a single rare region within the variational
instanton approach. For Heisenberg symmetry, the dynamics of the rare region is
studied using... | 1202.5562v3 |
2012-02-29 | MgyNi1-y(Hx) thin films deposited by magnetron co-sputtering | In this work we have synthesised thin films of MgyNi1-y(Hx) metal and metal
hydride with y between 0 and 1. The films are deposited by magnetron
co-sputtering of metallic targets of Mg and Ni. Metallic MgyNi1-y films were
deposited with pure Ar plasma while MgyNi1-yHx hydride films were deposited
reactively with 30% H2... | 1202.6484v1 |
2012-03-03 | Shock Induced Order-disorder Transformation in Ni3Al | The Hugoniot of Ni3Al with L12 structure is calculated with an equation of
state (EOS) based on a cluster expansion and variation method from first
principles. It is found that an order-disorder transition occurs at a shock
pressure of 205GPa, corresponding to 3750K in temperature. On the other hand,
an unexpected high... | 1203.0624v1 |
2012-03-06 | Robustness and stability of half-metallic ferromagnetism in alkaline-earth metal mononitrides against doping and deformation | We employ ab-initio electronic structure calculations and study the magnetic
properties of CaN and SrN compounds crystallizing in the rocksalt structure.
These alkaline-earth metal mononitrides are found to be half-metallic with a
total spin magnetic moment per formula unit of 1.0 $\mu_B$. The Curie
temperature is esti... | 1203.1106v2 |
2012-03-07 | Origin of magnetic interactions and their influence on the structural properties of Ni2MnGa and related compounds | In this work, we perform first principles DFT calculations to investigate the
interplay between magnetic and structural properties in Ni2MnGa. We demonstrate
that the relative stability of austenite (cubic) and non-modulated martensite
(tetragonal) phases depends critically on the magnetic interactions between Mn
atoms... | 1203.1553v1 |
2012-03-12 | Interface-driven phase separation in multifunctional materials: the case of GeMn ferromagnetic semiconductor | We use extensive first principle simulations to show the major role played by
interfaces in the mechanism of phase separation observed in semiconductor
multifunctional materials. We make an analogy with the precipitation sequence
observed in over-saturated AlCu alloys, and replace the Guinier-Preston zones
in this new ... | 1203.2417v2 |
2012-03-29 | Grain boundaries in ultrafine grained materials processed by severe plastic deformation and related phenomena | Grain boundaries in ultrafine grained (UFG) materials processed by severe
plastic deformation (SPD) are often called "non-equilibrium" grain boundaries.
Such boundaries are characterized by excess grain boundary energy, presence of
long range elastic stresses and enhanced free volumes. These features and
related phenom... | 1203.6496v1 |
2012-03-31 | A viscoplasticity model with an enhanced control of the yield surface distortion | A new model of metal viscoplasticity, which takes combined isotropic,
kinematic, and distortional hardening into account, is presented. The basic
modeling assumptions are illustrated using a new two-dimensional rheological
analogy. This demonstrative rheological model is used as a guideline for the
construction of cons... | 1204.0086v1 |
2012-04-06 | Optoelectronic Properties and Excitons in Hybridized Boron Nitride and Graphene Hexagonal Monolayers | We explain the nature of the electronic band gap and optical absorption
spectrum of Carbon - Boron Nitride (CBN) hybridized monolayers using density
functional theory (DFT), GW and Bethe-Salpeter equation calculations. The CBN
optoelectronic properties result from the overall monolayer bandstructure,
whose quasiparticl... | 1204.1542v1 |
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