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2009-10-23
Fast-ion conduction and flexibility and rigidity of solid electrolyte glasses
Electrical conductivity of dry, slow cooled (AgPO$_3$)$_{1-x}$(AgI)$_x$ glasses is examined as a function of temperature, frequency and glass composition. From these data compositional trends in activation energy for conductivity E$_A$(x), Coulomb energy E$_c$(x) for Ag$^+$ ion creation, Kohlrausch stretched exponent $...
0910.4508v1
2009-11-30
Mg/Ti multilayers: structural, optical and hydrogen absorption properties
Mg-Ti alloys have uncommon optical and hydrogen absorbing properties, originating from a "spinodal-like" microstructure with a small degree of chemical short-range order in the atoms distribution. In the present study we artificially engineer short-range order by depositing Pd-capped Mg/Ti multilayers with different pe...
0911.5666v1
2010-01-26
Structure and giant magnetoresistance of granular Co-Cu nanolayers prepared by cross-beam PLD
A series of Co_xCu_{100-x} (x = 0, 40...75, 100) layers with thicknesses in-between 13 nm and 55 nm were prepared on silicon substrates using cross-beam pulsed laser deposition. Wide-angle X-ray diffraction (WAXRD), transmission electron microscopy (TEM) and electrical transport measurements revealed a structure consis...
1001.4725v2
2010-01-28
A simple kinetic sensor to structural transitions
Driven non-equilibrium structural phase transformation has been probed using time varying resistance fluctuations or noise. We demonstrate that the non-Gaussian component (NGC) of noise obtained by evaluating the higher order statistics of fluctuations, serves as a simple kinetic detector of these phase transitions. Us...
1001.5137v1
2010-02-17
Measurement of Gilbert damping parameters in nanoscale CPP-GMR spin-valves
In-situ, device level measurement of thermal mag-noise spectral linewidths in 60nm diameter CPP-GMR spin-valve stacks of IrMn/ref/Cu/free, with reference and free layer of similar CoFe/CoFeGe alloy, are used to simultaneously determine the intrinsic Gilbert damping for both magnetic layers. It is shown that careful ali...
1002.3295v1
2010-03-06
From Graphene to Bismuth Telluride: Mechanical Exfoliation of Quasi-2D Crystals for Applications in Thermoelectrics and Topological Insulators
Bismuth telluride (Bi2Te3) and its alloys are the best bulk thermoelectric materials known today. The stacked quasi-two-dimensional (2D) layers of Bi2Te3 were also identified as topological insulators. In this paper we describe a method for graphene-inspired exfoliation of crystalline bismuth telluride films with a thi...
1003.1398v1
2010-06-04
Electronic structure and the glass transition in pnictide and chalcogenide semiconductor alloys. Part II: The intrinsic electronic midgap states
We propose a structural model that treats in a unified fashion both the atomic motions and electronic excitations in quenched melts of pnictide and chalcogenide semiconductors. In Part I (submitted to J. Chem. Phys.), we argued these quenched melts represent aperiodic $pp\sigma$-networks that are highly stable and, at ...
1006.0776v2
2010-07-15
First-principles data for solid-solution strengthening of magnesium: From geometry and chemistry to properties
Solid-solution strengthening results from solutes impeding the glide of dislocations. Existing theories of strength rely on solute-dislocation interactions, but do not consider dislocation core structures, which need an accurate treatment of chemical bonding. Here, we focus on strengthening of Mg, the lightest of all s...
1007.2585v1
2010-10-09
Phase field model for coupled displacive and diffusive microstructural processes under thermal loading
A non-isothermal phase field model that captures both displacive and diffusive phase transformations in a unified framework is presented. The model is developed in a formal thermodynamic setting, which provides guidance on admissible constitutive relationships and on the coupling of the numerous physical processes that...
1010.1871v2
2010-10-22
Noisy Kondo impurities
The anti-ferromagnetic coupling of a magnetic impurity carrying a spin with the conduction electrons spins of a host metal is the basic mechanism responsible for the increase of the resistance of an alloy such as Cu${}_{0.998}$Fe${}_{0.002}$ at low temperature, as originally suggested by Kondo . This coupling has emerg...
1010.4815v1
2010-11-06
Ab-initio study of the bandgap engineering of Al(1-x)Ga(x)N for optoelectronic applications
A theoretical study of Al(1-x)Ga(x)N, based on full-potential linearized augmented plane wave method, is used to investigate the variations in the bandgap, optical properties and non-linear behavior of the compound with the variation of Ga concentration. It is found that the bandgap decreases with the increase of Ga in...
1011.1573v1
2010-11-13
Fabrication and characterization of a Ni-Mn-Ga uniaxially textured freestanding film deposited by DC magnetron sputtering
Homogeneous freestanding films have been obtained by the direct current (DC) magnetron sputtering technique using a sacrificial layer. After annealing, the films are crystallized with a strong out-of-plane texture along the (022) direction. The stoichiometry of the annealed films is close to the target composition and ...
1011.3109v1
2010-11-15
Critical behavior of ferromagnetic pure and random diluted nanoparticles with competing interactions: variational and Monte Carlo approaches
The magnetic properties and critical behavior of both ferromagnetic pure and metallic nanoparticles having concurrently atomic disorder, dilution and competing interactions, are studied in the framework of an Ising model. We have used both the free energy variational principle based on the Bogoliubov inequality and Mon...
1011.3388v1
2010-12-15
Non-collinear magnetism in freestanding and supported monatomic Mn chains
Using first-principles calculations, we study the occurrence of non-collinear magnetic order in monatomic Mn chains. First, we focus on freestanding Mn chains and demonstrate that they exhibit a pronounced non-collinear ground state in a large range of interatomic distances between atoms in the chain. By artificially v...
1012.3413v2
2010-12-17
Modulated Martensite: Why it forms and why it deforms easily
Diffusionless phase transitions are at the core of the multifunctionality of (magnetic) shape memory alloys, ferroelectrics and multiferroics. Giant strain effects under external fields are obtained in low symmetric modulated martensitic phases. We outline the origin of modulated phases, their connection with tetragona...
1012.3914v2
2011-03-05
Physics and measurements of magnetic materials
Magnetic materials, both hard and soft, are used extensively in several components of particle accelerators. Magnetically soft iron-nickel alloys are used as shields for the vacuum chambers of accelerator injection and extraction septa; Fe-based material is widely employed for cores of accelerator and experiment magnet...
1103.1069v1
2011-05-13
First Principles Calculations of Defects in Unstable Crystals: Austenitic Iron
First principles calculations have given a new insight into the energies of point defects in many different materials, information which cannot be readily obtained from experiment. Most such calculation are done at zero Kelvin, with the assumption that finite temperature effects on defect energies and barriers are smal...
1105.2663v1
2011-05-26
Prediction of thermal cross-slip stress in magnesium alloys from direct first principles data
We develop a first-principles model of thermally-activated cross-slip in magnesium in the presence of a random solute distribution. Electronic structure methods provide data for the interaction of solutes with prismatic dislocation cores and basal dislocation cores. Direct calculations of interaction energies are possi...
1105.5365v1
2011-06-01
Enhancement-mode buried strained silicon channel quantum dot with tunable lateral geometry
We propose and demonstrate a relaxed-SiGe/strained-Si (SiGe/s-Si) enhancement-mode gate stack for quantum dots. The enhancement-mode SiGe/s-Si structure is pursued because it spaces the quantum dot away from charge and spin defect rich dielectric interfaces and minimizes background dopants. A mobility of 1.6\times10^5 ...
1106.0337v1
2011-06-03
Spectrum standardization for laser-induced breakdown spectroscopy measurements
This paper presents a spectra normalization method for laser-induced breakdown spectroscopy (LIBS) measurements by converting the recorded characteristic line intensity at varying conditions to the intensity under a standard condition with standard plasma temperature, degree of ionization, and total number density of t...
1106.0583v1
2011-06-28
An effective medium approach to the asymptotics of the statistical moments of the parabolic Anderson model and Lifshitz tails
Originally introduced in solid state physics to model amorphous materials and alloys exhibiting disorder induced metal-insulator transitions, the Anderson model $H_{\omega}= -\Delta + V_{\omega} $ on $l^2(\bZ^d)$ has become in mathematical physics as well as in probability theory a paradigmatic example for the relevanc...
1106.5728v1
2011-08-01
Theoretical study of magnetic properties and hyperfine interactions in $σ$-FeV alloys
Electronic structure Korringa-Kohn-Rostoker calculations for the $\sigma$-phase in Fe$_{100-x}$V$_x$ were performed in compositional range of its occurance ($\sim 34 \le x \le \sim 65$). Fe and V magnetic moments and hyperfine fields were determined for five inequivalent lattice sites in two models of magnetic structur...
1108.0278v1
2011-08-19
Structure and magnetic properties of nanostructured Pd-Fe thin films produced by pulse electrodeposition
Nanostructured Pd-Fe thin films with varied Fe content were prepared by electrodeposition technique from organic electrolytes on Cu and brass substrates. The structure and the magnetic properties of the films were investigated prior to post-deposition annealing. The structure of the Pd1-xFex thin films with x = 0.14, 0...
1108.3888v1
2011-09-08
Low-temperature structure of xi'-Al-Pd-Mn optimized by ab-initio methods
We have studied and resolved occupancy correlations in the existing average structure model of the complex metallic alloy xi'-Al-Pd-Mn [Boudard et al., Phil. Mag. A, 74, 939 (1996)], which has approximately 320 atoms in the unit cell and many fractionally occupied sites. Model variants were constructed systematically i...
1109.1687v2
2011-09-15
Characterization of Thin Pixel Sensor Modules Interconnected with SLID Technology Irradiated to a Fluence of 2$\cdot 10^{15}$\,n$_{\mathrm{eq}}$/cm$^2$
A new module concept for future ATLAS pixel detector upgrades is presented, where thin n-in-p silicon sensors are connected to the front-end chip exploiting the novel Solid Liquid Interdiffusion technique (SLID) and the signals are read out via Inter Chip Vias (ICV) etched through the front-end. This should serve as a ...
1109.3299v2
2011-10-12
First-principles study of magnetism, structure and chemical order in 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. The correlation between structure, chemical order, and magnetic behavior is analyzed as a function...
1110.2669v1
2011-12-02
Structural and optical studies of FeSb2 under high pressure
Nanostructured orthorhombic FeSb2 and an amorphous phase were formed by mechanical alloying starting from a mixture of high purity elemental Fe and Sb powders. The effects of high pressures on structural and optical properties were studied using X-ray diffraction (XRD) and Raman spectroscopy (RS). XRD patterns showed t...
1112.0468v1
2011-12-19
Quantum-Hall plateau-plateau transition in top-gated epitaxial graphene grown on SiC (0001)
We investigate the low-temperature magneto-transport properties of monolayer epitaxial graphene films formed on the Si-face of semi-insulating 4H-SiC substrates by a high temperature sublimation process. A high-k top-gate on the epitaxial graphene is realized by inserting a fully oxidized nanometer thin aluminum film a...
1112.4345v2
2012-01-11
Critical fields and growth rates of the Tayler instability as probed by a columnar gallium experiment
Many astrophysical phenomena (such as the slow rotation of neutron stars or the rigid rotation of the solar core) can be explained by the action of the Tayler instability of toroidal magnetic fields in the radiative zones of stars. In order to place the theory of this instability on a safe fundament it has been realize...
1201.2318v3
2012-01-30
Composition-dependent interatomic potentials: A systematic approach to modelling multicomponent alloys
We propose a simple scheme to construct composition-dependent interatomic potentials for multicomponent systems that when superposed onto the potentials for the pure elements can reproduce not only the heat of mixing of the solid solution in the entire concentration range but also the energetics of a wider range of con...
1201.6284v1
2012-02-07
Telecommunication band InAs quantum dots and dashes embedded in different barrier materials
We investigate the long wavelength (1.2 to 1.55 micro-m) photoluminescence of high-density InAs quantum dots and dashes, which were grown on InP substrates. We analyze the temperature dependence of the recombination and carrier distribution on the alloy composition of the barrier materials, InGaAlAs, and on the existen...
1202.1360v1
2012-02-08
Thermodynamic analysis of the Quantum Critical behavior of Ce-lattice compounds
A systematic analysis of low temperature magnetic phase diagrams of Ce compounds is performed in order to recognize the thermodynamic conditions to be fulfilled by those systems to reach a quantum critical regime and, alternatively, to identify other kinds of low temperature behaviors. Based on specific heat ($C_m$) an...
1202.1724v1
2012-03-13
Membrane-based nanocalorimeter for high-resolution measurements of low-temperature specific heat
A differential, membrane-based nanocalorimeter for general specific heat studies of very small samples, ranging from 0.5 mg to sub-{\mu}g in mass, is described. The calorimeter operates over the temperature range from above room temperature down to 0.5 K. It consists of a pair of cells, each of which is a stack of heat...
1203.2838v1
2012-03-14
Magnetic Interactions in Ge/1-x/Cr/x/Te Semimagnetic Semiconductors
We present the studies of magnetic properties of Ge/1-x/Cr/x/Te diluted magnetic semiconductor with changeable chemical composition 0.016 \leq x \leq 0.061. A spin-glass state (at T \leq 35 K) for x = 0.016 and 0.025 and a ferromagnetic phase (at T < 60 K) for x \geq 0.030 are observed. The long range carrier-mediated ...
1203.3044v2
2012-04-21
Ab-initio study of different structures of CaC: Magnetism, Bonding, and Lattice Dynamics
On the basis of ab-initio pseudopotential calculations, we study structural, magnetic, dynamical, and mechanical properties of the hypothetical CaC ionic compound in the rock-salt (RS), B2, zinc-blende (ZB), wurtzite (WZ), NiAs (NA), anti-NiAs (NA*), and CrB (B33) structures. It is argued that the ZB, WZ, NA, and RS st...
1204.4781v2
2012-05-10
Development of liquid helium-3 target for experimental studies of antikaon-nucleon interaction at J-PARC
A liquid helium-3 target system was developed for experimental studies of kaonic atoms and kaonic nuclei at J-PARC. helium-3 gas is liquefied in a heat exchanger cooled below 3.2 K by decompression of liquid helium-4. To maintain a large acceptance of the cylindrical detector system for decay particles of kaonic nuclei...
1205.2183v1
2012-06-04
Phase stability, elastic, electronic, thermal and optical properties of Ti3Al1-xSixC2 (0 LE x LE 1): First-principles study
The structural parameters with stability upon Si incorporation and elastic, electronic, thermodynamic and optical properties of Ti3Al1-xSixC2 (0 \leq x \leq 1) are investigated systematically by the plane wave psedudopotential method based on the density functional theory (DFT). The increase of some elastic parameters ...
1206.0545v2
2012-06-04
Modern consumerism and the waste problem
With the advance of industrial mass production, modern micro-electronics and computers, the intervals between the release of new generations of consumer products have been dramatically reduced and so have their lifetime cycles. While it was very natural in the post-war era, that sophisticated consumer products like tel...
1206.0604v1
2012-06-04
Spin texture on the Fermi surface of tensile strained HgTe
We present ab initio and k.p calculations of the spin texture on the Fermi surface of tensile strained HgTe, which is obtained by stretching the zincblende lattice along the (111) axis. Tensile strained HgTe is a semimetal with pointlike accidental degeneracies between a mirror symmetry protected twofold degenerate ban...
1206.0684v2
2012-06-04
Topological Surface States and Dirac point tuning in ternary Bi2Te2Se class of topological insulators
Using angle-resolved photoemission spectroscopy, we report electronic structure for representative members of ternary topological insulators. We show that several members of this family, such as Bi2Se2Te, Bi2Te2Se, and GeBi2Te4, exhibit a singly degenerate Dirac-like surface state, while Bi2Se2S is a fully gapped insul...
1206.0695v2
2012-06-11
Observation of Topological Crystalline Insulator phase in the lead tin chalcogenide Pb1-xSnxTe material class
We perform systematic angle-resolved photoemission spectroscopic measurements on the lead tin telluride Pb1-xSnxTe pseudobinary alloy system. We show that the (001) crystalline surface, which is a crystalline surface symmetric about the (110) mirror planes of the Pb1-xSnxTe crystal, pos- sesses four metallic surface st...
1206.2088v1
2012-08-10
Precise calibration of Mg concentration in MgxZn1-xO thin films grown on ZnO substrates
The growth techniques for MgxZn1-xO thin films have advanced at a rapid pace in recent years, enabling the application of this material to a wide range of optical and electrical applications. In designing structures and optimizing device performances, it is crucial that the Mg content of the alloy be controllable and p...
1208.2074v1
2012-08-16
High superconducting anisotropy and weak vortex pinning in Co doped LaFeAsO
Here, we present an electrical transport study in single crystals of LaFe$_{0.92}$Co$_{0.08}$AsO ($T_c \simeq 9.1$ K) under high magnetic fields. In contrast to most of the previously reported Fe based superconductors, and despite its relatively low $T_c$, LaFe$_{1-x}$Co$_x$AsO shows a superconducting anisotropy which ...
1208.3435v1
2012-10-09
La fonte algébrique des Méthodes nouvelles de la mécanique céleste d'Henri Poincaré
Poincar\'e's approach to the three body problem has often been celebrated as a starting point of chaos theory in relation to the investigation of dynamical systems. Yet, Poincar\'e's strategy can also be analyzed as molded on - or casted in - some specific algebraic practices for manipulating systems of linear equation...
1210.2673v1
2012-10-11
Quantum critical state in a magnetic quasicrystal
Quasicrystals are metallic alloys that possess long-range, aperiodic structures with diffraction symmetries forbidden to conventional crystals. Since the discovery of quasicrystals by Schechtman et al. at 1984 (ref. 1), there has been considerable progress in resolving their geometric structure. For example, it is well...
1210.3160v1
2012-11-02
Direct Observation of Giant Saturation Magnetization in Fe16N2
Magnetic materials with giant saturation magnetization have been a holy grail for magnetic researchers and condensed matter physicists for decades because of its great scientific and technological impacts. As described by the famous Slater-Pauling curve the material with highest Ms is the Fe65Co35 alloy. This was chall...
1211.0553v1
2012-11-05
Structure and Thermodynamical Properties of Zirconium hydrides from first-principle
Zirconium alloys are used as nuclear fuel cladding material due to their mechanical and corrosion resistant properties together with their favorable cross-section for neutron scattering. At running conditions, however, there will be an increase of hydrogen in the vicinity of the cladding surface at the water side of th...
1211.0858v1
2012-12-04
Application of photoreflectance to advanced multilayer structures for photovoltaics
Photoreflectance (PR) is a convenient characterization tool able to reveal optoelectronic properties of semiconductor materials and structures. It is a simple non-destructive and contactless technique which can be used in air at room temperature. We will present experimental results of the characterization carried out ...
1212.0680v1
2012-12-07
Binding of an oxide layer to a metal: the case of Ti(10-10)/TiO2(100)
We study the chemical nature of the bonding of an oxide layer to the parent metal. In order to disentangle chemical effects from strain/misfit, Ti(10$\bar{1}$0)/TiO$_{2}$(100) interface has been chosen. We use the density functional pseudopotential method which gives good agreement with experiment for known properties ...
1212.1659v1
2013-01-02
Ab initio calculation of anisotropic interfacial excess free energies
We describe a simple method to determine, from ab initio calculations, the complete orientation-dependence of interfacial free energies in solid-state crystalline systems. We illustrate the method with an application to precipitates in the Al-Ti alloy system. The method combines the cluster expansion formalism in its m...
1301.0168v2
2013-01-29
Cluster packing geometry for Al-based F-type icosahedral alloys
This paper presents a new highly stable periodic approximant to the Al-based F-type icosahedral quasicrystals, i-Al-Pd-TM (TM=transition metals). The structure of this intermetallic Al-Pd-Cr-Fe compound is determined ab initio using single-crystal X-ray diffraction, where the space group is identified to be Pa-3 and th...
1301.6823v1
2013-02-08
The hybrid lattice of KxFe2-ySe2: why superconductivity and magnetism can coexist
Much remains unknown of the microscopic origin of superconductivity when it materializes in atomically disordered systems as in amorphous alloys (1) or in crystals riddled with defects(2). A manifestation of this conundrum is envisaged in the highly defective iron chalcogenide superconductors of KxFe2-ySe2 (3-6). How c...
1302.2162v1
2013-02-15
Road to room-temperature superconductivity: A universal model
In a semiclassical view superconductivity is attributed exclusively to the advance of atoms' outer s electrons through the nuclei of neighbor atoms in a solid. The necessary progression of holes in the opposite direction has the electric and magnetic effect as if two electrons were advancing instead of each actual one....
1302.5043v2
2013-03-02
Determination of the Stopping Power and Failure-time of Spacecraft Components due to Proton Interaction Using GOES 11 Acquisition Data
One of the several ways to describe the net effect of charged-particles' interaction is the rate of energy loss along the particles' path. In this study, the mass stopping power (Sp) of selected spacecraft composite materials, through which the particle traverses, its range (R) and the distance (d) travelled (by the pa...
1303.0434v1
2013-03-07
On a dislocation density based two-phase plasticity model: refinement and extension to non-proportional loading
The two-phase composite approach of Estrin et al. (1998) describes an evolving dislocation cell structure. Mckenzie et al. (2007) enhanced the model to capture the effects of hydrostatic pressure and temperature during severe plastic deformation. The goal of the present study is to incorporate this microstructural mode...
1303.1731v1
2013-04-04
RKKY interaction in heavily vacant graphene
Dirac electrons in clean graphene can mediate the interactions between two localized magnetic moments. The functional form of the RKKY interaction in pristine graphene is specified by two main features: (i) an atomic scale oscillatory part determined by a wave vector $\vec Q$ connecting the two valleys. Furthermore wit...
1304.1272v1
2013-04-24
General Phase-Field Model with Stability Requirements on Interfaces in $N$-Dimensional Phase-Field Space
In this paper a general multi-phase-field model is presented which is an extension and modification of the model proposed by Folch and Plapp for three phase fields [R. Folch and M. Plapp, Phys. Rev. E 72 011602 (2005)] to the arbitrary number of phases. In the model a physical constraint requiring that the sum of all p...
1304.6549v2
2013-04-30
Universal scaling in disordered systems and non-universal exponents
The effect of an electric field on conduction in a disordered system is an old but largely unsolved problem. Experiments cover an wide variety of systems - amorphous/doped semiconductors, conducting polymers, organic crystals, manganites, composites, metallic alloys, double perovskites - ranging from strongly localized...
1305.0031v2
2013-05-10
Multi-q Pattern Classification of Polarization Curves
Several experimental measurements are expressed in the form of one-dimensional profiles, for which there is a scarcity of methodologies able to classify the pertinence of a given result to a specific group. The polarization curves that evaluate the corrosion kinetics of electrodes in corrosive media are an application ...
1305.2876v1
2013-05-16
Different routes to pressure-induced volume collapse transitions in gadolinium and terbium metals
The sudden decrease in molar volume exhibited by most lanthanides under high pressure is often attributed to changes in the degree of localization of their 4f-electrons. We give evidence, based on electrical resistivity measurements of dilute Y(Gd) and Y(Tb) alloys to 120 GPa, that the volume collapse transitions in Gd...
1305.3852v4
2013-06-04
Majorana bound states in d-wave superconductor-based hybrid systems
For the search of Majorana fermions, we propose to employ a ramp-type Josephson edge junction between a normal metal such as Au, Ag or alloys of heavy metals and a topologically-trivial dx2-y2 wave high-Tc superconductor YBa2Cu3O7. The success in forming the elusive zero-energy Majorana bound states (MBS) at the juncti...
1306.0652v2
2013-06-14
Magnetic structures of Mn3-xFexSn2: an experimental and theoretical study
We investigate the magnetic structure of Mn3-xFexSn2 using neutron powder diffraction experiments and electronic structure calculations. These alloys crystallize in the orthorhombic Ni3Sn2 type of structure (Pnma) and comprise two inequivalent sites for the transition metal atoms (4c and 8d) and two Sn sites (4c and 4c...
1306.3339v1
2013-06-18
Magnetic anisotropy and lattice dynamics in FeAs studied by Mössbauer spectroscopy
Iron mono-arsenide in the powder form has been investigated by transmission 57Fe Moessbauer spectroscopy in the temperature range 4.2 - 1000 K. Additional spectra have been obtained at 20 K and 100 K applying external magnetic field of 7 T. It was found that the spin spiral propagating along the c-axis leads to the com...
1306.4170v3
2013-06-18
Thermoelectric effects and the asymmetry of the current-voltage characteristics of metallic point contacts
An asymmetry as a function of the direction of current flow is observed in the current-voltage characteristic (CVC) and its first and second derivatives for point heterocontacts between pure metals {Cu, Ni, Fe) as well as between these metals and dilute alloys (CuFe, CuMn). It is shown that the observed asymmetry is ca...
1306.4189v1
2013-06-28
Impact of sintering temperature on room temperature magneto-resistive and magneto-caloric properties of Pr2/3Sr1/3MnO3
Magneto-resistive and magneto-caloric properties of polycrystalline Pr2/3Sr1/3MnO3 have been studied as a function of sintering temperature (Ts) between 1260-1450{\deg}C. Reitveld refinement of their X-ray diffraction (XRD) patterns confirms their single phase crystalline structure with orthorhombic Pbnm space group. T...
1306.6792v2
2013-07-01
Electronic fine structure in the nickel carbide superconductor Th$_{2}$NiC$_{2}$
The recently reported nickel carbide superconductor, body centered tetragonal $I4/mmm$ Th$_2$NiC$_2$ with T$_c$ = 8.5 K increasing to 11.2 K upon alloying Th with Sc, is found to have very fine structure in its electronic spectrum, according to density functional based first principles calculations. The filled Ni 3d ba...
1307.0415v1
2013-07-09
Neutron diffraction evidence for kinetic arrest of first-order magneto-structural phase transitions in some functional magnetic materials
Neutron diffraction measurements, performed in presence of an external magnetic field, have been used to show structural evidence for the kinetic arrest of the first-order phase transition from (i) the high temperature austenite phase to the low temperature martensite phase in the magnetic shape memory alloy Ni37Co11Mn...
1307.2486v3
2013-09-10
Thermodynamic interpretation of reactive processes in Ni-Al nanolayers from atomistic simulations
Metals which can form intermetallic compounds by an exothermic reaction constitute a class of reactive materials with multiple applications. Ni-Al laminates of thin alternating layers are being considered as model nanometric metallic multilayers for studying various reaction processes. However, the reaction kinetics at...
1309.2664v3
2013-09-12
Thermodynamic Stability of Mg-based Ternary Long-Period Stacking Ordered Structures
Mg alloys containing long-period stacking ordered (LPSO) structures exhibit remarkably high tensile yield strength and ductility. They have been found in a variety of ternary Mg systems of the general form Mg-XL-XS, where XL and XS are elements larger and smaller than Mg, respectively. In this work, we examine the ther...
1309.3184v1
2013-10-25
The effect of a micro bubble dispersed gas phase on hydrogen isotope transport in liquid metals under nuclear irradiation
The present work intend to be a first step towards the understanding and quantification of the hydrogen isotope complex phenomena in liquid metals for nuclear technology. Liquid metals under nuclear irradiation in,e.g., breeding blankets of a nuclear fusion reactor would generate tritium which is to be extracted and re...
1310.6875v1
2013-10-28
Analysis of interior penalty discontinuous Galerkin methods for the Allen-Cahn equation and the mean curvature flow
This paper develops and analyzes two fully discrete interior penalty discontinuous Galerkin (IP-DG) methods for the Allen-Cahn equation, which is a nonlinear singular perturbation of the heat equation and originally arises from phase transition of binary alloys in materials science, and its sharp interface limit (the m...
1310.7504v2
2013-11-07
Crystal lattice rules disordered states
Based on classical statistical thermodynamics, we develop a theoretical approach that provides new insight into how macroscopic and microscopic physical properties are bridged via crystal lattice for condensed mat- ters. We find that in order to determine macroscopic physical properties and their temperature dependence...
1311.1664v7
2013-11-14
Electric field gradient wave (EFGW) in iron-based superconductor Ba(0.6)K(0.4)Fe2As2 studied by Mössbauer spectroscopy
The optimally doped 122 iron-based superconductor Ba(0.6)K(0.4)Fe2As2 has been studied by 57Fe Moessbauer spectroscopy versus temperature ranging from 4.2 K till 300 K with particular attention paid to the superconducting transition around 38 K. The spectra do not contain magnetic components and they exhibit quasi-cont...
1311.3503v4
2013-11-21
Reducing beam hardening effects and metal artefacts using Medipix3RX: With applications from biomaterial science
This paper discusses methods for reducing beam hardening effects using spectral data for biomaterial applications. A small-animal spectral scanner operating in the diagnostic energy range was used. We investigate the use of photon-processing features of the Medipix3RX ASIC in reducing beam hardening and associated arte...
1311.5303v1
2013-11-26
Recent Progress in III-V based ferromagnetic semiconductors: Band structure, Fermi level, and tunneling transport
Spin-based electronics or spintronics is an emerging field, in which we try to utilize spin degrees of freedom as well as charge transport in materials and devices. While metal-based spin-devices, such as magnetic-field sensors and magnetoresistive random access memory using giant magnetoresistance and tunneling magnet...
1311.6616v1
2014-01-16
Homogeneous limit of Cd(1-x)Mn(x)GeAs(2) alloy: electrical and magnetic properties
We present the studies of structural, electrical, and magnetic properties of bulk Cd$_{1\textrm{-}x}$Mn$_{x}$GeAs$_{2}$ crystals with low Mn content, $x$, varying from 0 to 0.037. The studied samples have excellent crystallographic quality indicated by the presence of diffraction patterns never before observed experime...
1401.4037v2
2014-01-18
Predicting the steady state thickness of passive films in order to prevent degradations of implant
Some implants have approximately a lifetime of 15 years. The femoral stem, for example, should be made of 316L/316LN stainless steel. Fretting corrosion, friction under small displacements, should occur during human gait, due to repeated loadings and un-loadings, between stainless steel and bone for instance. Some expe...
1401.4570v1
2014-02-10
Tuning the band gap of PbCrO4 through high-pressure: Evidence of wide-to-narrow semiconductor transitions
The electronic transport properties and optical properties of lead(II) chromate (PbCrO4) have been studied at high pressure by means of resistivity, Hall-effect, and optical-absorption measurements. Band-structure first-principle calculations have been also performed. We found that the low-pressure phase is a direct ba...
1402.2139v1
2014-03-06
Quadrupolar induced suppression of nuclear spin bath fluctuations in self-assembled quantum dots
Decoherence in quantum logic gates (qubits) due to interaction with the surrounding environment is a major obstacle to the practical realization of quantum information technologies. For solid state electron-spin qubits the interaction with nuclear spins is the main problem. One particular, neradicable source of electro...
1403.1510v2
2014-03-19
Pt-based nanowire networks with enhanced oxygen-reduction activity
Pt-Al and Pt-Y-Al thin film electrodes on yttria-stabilised zirconia electrolytes were prepared by dealloying of co-sputtered Pt-Al or Pt-Y-Al films. The selective dissolution of Al from the Pt-alloy compound causes the formation of a highly porous nanowire network with a mean branch thickness below 25 nm and a pore in...
1403.4665v4
2014-03-31
Tensile strained $In_{x}Ga_{1-x}P$ membranes for cavity optomechanics
We investigate the optomechanical properties of tensile-strained ternary InGaP nanomembranes grown on GaAs. This material system combines the benefits of highly strained membranes based on stoichiometric silicon nitride, with the unique properties of thin-film semiconductor single crystals, as previously demonstrated w...
1404.0029v1
2014-04-15
Muon spin rotation and relaxation in Pr$_{1-x}$Nd$_x$Os$_4$Sb$_{12}$: Magnetic and superconducting ground states
Muon spin rotation and relaxation ($\mu$SR) experiments have been carried out to characterize magnetic and superconducting ground states in the Pr$_{1-x}$Nd$_x$Os$_4$Sb$_{12}$ alloy series. In the ferromagnetic end compound NdOs$_4$Sb$_{12}$ the spontaneous local field at positive-muon ($\mu^+$) sites below the orderin...
1404.4090v1
2014-04-16
Origin of High Temperature Oxidation Resistance of Ti-Al-Ta-N Coatings
Alloying Ti-Al-N coatings with Ta has proven to enhance their hardness, thermal stability, and oxidation resistance. However, especially for arc-evaporated Ti-Al-Ta-N coatings only limited information on the detailed influence of the elements on various properties is available. Therefore, we have developed arc-evaporat...
1404.4345v1
2014-04-07
Liquid Metal as Connecting or Functional Recovery Channel for the Transected Sciatic Nerve
In this article, the liquid metal GaInSn alloy (67% Ga, 20.5% In, and 12.5% Sn by volume) is proposed for the first time to repair the peripheral neurotmesis as connecting or functional recovery channel. Such material owns a group of unique merits in many aspects, such as favorable fluidity, super compliance, high elec...
1404.5931v1
2014-05-01
Helical Antiferromagnetic Ordering in Lu{1-x}Sc{x}MnSi (x = 0, 0.25, 0.50)
Polycrystalline samples of Lu{1-x}Sc{x}MnSi (x= 0, 0.25, 0.50) are studied using powder x-ray diffraction (XRD), heat capacity Cp, magnetization M, magnetic susceptibility chi, and electrical resistivity rho measurements versus temperature T and magnetic field H. This system crystallizes in the primitive orthorhombic T...
1405.0202v1
2014-05-26
Amorphous ferromagnetism and re-entrant magnetic glassiness in Sm$_{2}$Mo$_{2}$O$_{7}$: new insights into the electronic phase diagram of pyrochlore molybdates
We discuss the magnetic properties of a Sm$_{2}$Mo$_{2}$O$_{7}$ single crystal as investigated by means of different experimental techniques. In the literature, a conventional itinerant ferromagnetic state is reported for the Mo$^{4+}$ sublattice below $\sim 78$ K. However, our results of dc magnetometry, muon spin spe...
1405.6608v1
2014-07-21
Pressure-induced giant enhancement of magnetocaloric effects in MnNiSi-based systems
A remarkable decrease of the structural transition temperature of MnNiSi from 1200 K to <300 K by chemically alloying it with MnFeGe results in a coupling of the magnetic and structural transitions, leading to a large magnetocaloric effect near room temperature. It was found that the magnetostructural transition is hig...
1407.5689v1
2014-08-01
Ab initio study of InxGa(1-x)N - performance of the alchemical mixing approximation
The alchemical mixing approximation which is the ab initio pseudopotential specific implementation of the virtual crystal approximation (VCA), offered in the ABINIT package, has been employed to study the wurtzite (WZ) and zinc blende (ZB) InxGa(1-x)N alloy from first principles. The investigations were focused on stru...
1408.0106v1
2014-08-25
Synthesis of Component and Connector Models from Crosscutting Structural Views
We present component and connector (C&C) views, which specify structural properties of component and connector models in an expressive and intuitive way. C&C views provide means to abstract away direct hierarchy, direct connectivity, port names and types, and thus can crosscut the traditional boundaries of the implemen...
1408.5696v1
2014-09-03
DC magnetization studies of nano- and micro-particles of bilayered manganite LaSr2Mn2O7
Systematic studies of magnetic properties of LaSr2Mn2O7 as a function of crystalline grain size provide information on how the crystalline grain size affects the magnetic and charge ordering in this compound. The half-doped bi-layered manganite LaSr2Mn2O7 (x=0.5) in its bulk form has CE-type antiferromagnetic (CE-AFM) ...
1409.0945v2
2014-09-11
Anisotropic magnetoresistance in antiferromagnetic Sr2IrO4
We report point-contact measurements of anisotropic magnetoresistance (AMR) in a single crystal of antiferromagnetic (AFM) Mott insulator Sr2IrO4. The point-contact technique is used here as a local probe of magnetotransport properties on the nanoscale. The measurements at liquid nitrogen temperature revealed negative ...
1409.3491v2
2014-09-24
Radiation-induced softening of Fe and Fe-based alloys during in-situ electron irradiation under mechanical testing
Defects formed under irradiation in the bulk act as additional pinning centers resulting in the well-known effect of radiation-induced hardening. On the other hand, there is a poorly understood but well-established effect of instant and reversible softening of metals subjected to various types of irradiation. This radi...
1409.6799v1
2014-10-01
Evidence for magnetic clusters in Ni$_{1-x}$V$_{x}$ close to the quantum critical concentration
The d-metal alloy Ni$_{1-x}$V$_{x}$ undergoes a quantum phase transition from a ferromagnetic ground state to a paramagnetic ground state as the vanadium concentration $x$ is increased. We present magnetization, ac-susceptibility and muon-spin relaxation data at several vanadium concentrations near the critical concent...
1410.0094v1
2014-10-27
Self-assembly of the decagonal quasicrystalline order in simple three-dimensional systems
For a three dimensional system we answer two questions, how simple a particle system might be to show the quasicrystal order and, what system features are the most important for quasicrystal formation? One-component system of particles with isotropic pair interaction is one of the simplest ones. We show that such syste...
1410.7294v4
2014-10-31
Local character of the highest antiferromagnetic Ce-system CeTi{1-x}Sc{x} Ge
The highest antiferromagnetic (AFM) temperature in Ce based compounds has been reported for CeScGe with Tn=47K, but its local or itinerant nature was not deeply investigated yet. In order to shed more light into this unusually high ordering temperature we have investigated structural, magnetic, transport and thermal pr...
1410.8850v1
2014-11-10
Parameter estimation in spherical symmetry groups
This paper considers statistical estimation problems where the probability distribution of the observed random variable is invariant with respect to actions of a finite topological group. It is shown that any such distribution must satisfy a restricted finite mixture representation. When specialized to the case of dist...
1411.2540v2
2014-11-13
Quantum Critical Fluctuations in the Heavy fermion compound Ce(Ni$_{0.935}$Pd$_{0.065}$)$_2$Ge$_2$
Electric resistivity, specific heat, magnetic susceptibility, and inelastic neutron scattering experiments were performed on a single crystal of the heavy fermion compound Ce(Ni$_{0.935}$Pd$_{0.065}$)$_2$Ge$_2$ in order to study the spin fluctuations near an antiferromagnetic (AF) quantum critical point (QCP). The resi...
1411.3689v1
2014-12-10
Enhancement and reduction of one-dimensional heat conduction with correlated mass disorder
Short-range order in strongly disordered structures plays an important role in their heat conduction property. Using numerical and analytical methods, we show that short-range spatial correlation (with a correlation length of $\Lambda_{m}$) in the mass distribution of the one-dimensional (1D) alloy-like random binary l...
1412.3214v1
2014-12-19
Nonlocality in microscale heat conduction
Thermal transport at short length and time scales inherently constitutes a nonlocal relation between heat flux and temperature gradient, but this is rarely addressed explicitly. Here, we present a formalism that enables detailed characterisation of the delocalisation effects in nondiffusive heat flow regimes. A convolu...
1412.6555v2
2014-12-23
First-principles calculations of indirect Auger recombination in nitride semiconductors
Auger recombination is an important non-radiative carrier recombination mechanism in many classes of optoelectronic devices. The microscopic Auger processes can be either direct or indirect, mediated by an additional scattering mechanism such as the electron-phonon interaction. Phonon-assisted Auger recombination is pa...
1412.7555v2