Optical measurements are performed near the fundamental absorption edge for single-crystal AlxGa1−x N epitaxial layers in composition range of 0≤x≤0.4. The dependence energy band gap on is found to deviate downwards from linearity, bowing parameter being b=1.0±0.3 eV. origin large discussed terms pseudopotential Al and Ga based Heine–Abarenkov type. With increasing x edges broaden, which attributed increase compositional nonuniformity.

For the study of ferromagnetic materials which are compatible with group-IV semiconductor spintronics, we demonstrate control properties Heusler-alloy Fe3-xMnxSi epitaxially grown on Ge(111) by tuning Mn composition x. Interestingly, obtain L2(1)-ordered structures even for nonstoichiometric atomic compositions. The Curie temperature epilayers x approximately 0.6 exceeds 300 K. Theoretical calculations indicate that electronic alloys become half-metallic 0.75 < or = 1.5. We discuss...

We study the effect of disorder on intrinsic anomalous Hall conductivity in a magnetic two-dimensional electron gas with Rashba-type spin-orbit interaction. find that vanishes unless lifetime is spin-dependent, similar to spin nonmagnetic system. In addition, we does not vanish presence scatterers.

Abstract: A centrifugal blood pump with a magnetically suspended impeller has been developed. It single inlet and outlet, it generates forces by the rotating impeller. The fluid‐dynamical design for inflow outflow through leads to elimination of axial force unbalanced radial acting on Consequently, three‐component control systems, instead five‐component ones, are enough position rotates magnetic coupling permanent magnets embedded in outer rotator motor. This performance function as pump....

Nanoelectronic devices based on electron spin can overcome the physical limitations of present semiconductor technology because their low power consumption while exploiting degree freedom electrons. Although enhancing efficiency generation current is imperative and a primary issue for practical application spin-based electronics, seamless device integration with conventional complementary metal-oxide another important milestone developing nanoelectronics. In particular, preparation...

We calculate the electronic states of Mn-doped semiconductors and show that resonant are formed at top down spin valence band due to magnetic impurities they give rise a strong long-ranged ferromagnetic coupling between Mn moments. propose states, in addition intra-atomic exchange interaction nonbonding is origin ferromagnetism (Ga-Mn)As. The mechanism thus called "double resonance." bring about spin-dependent resistivity produce magnetoresistive properties (Ga-Mn)As their junctions.

The microscopic origin of the giant magnetoresistance in metallic superlattices is ascribed to spin-dependent random exchange potential caused by roughness interfaces. determined self-consistently calculating electronic structure and magnetic moments near interfaces for Fe/TM Co/TM superlattices, where TM's denote transition-metal elements. tight-binding d-band model recursion method are used calculation. lifetime electrons estimated from imaginary part self-energy produced scattering...

$D{0}_{3}$-ordered Fe${}_{3}$Si, which is one of the ferromagnetic Heusler compounds, has so far been formed by high-temperature heat treatments. Here, we demonstrate room-temperature $D{0}_{3}$ ordering Fe${}_{3}$Si films grown on Ge(111) using a molecular beam epitaxy (MBE) technique. In our MBE conditions, higher growth temperatures are not effective to obtain highly ordered structures because interfacial reactions between and Ge. Even for growth, degree can be improved with increasing...

Electrical resistivity, thermoelectric power and thermal conductivity due to random exchange potentials at the interfaces of magnetic superlattices are theoretically studied. Material dependence these properties is derived for TM/Cu superlattices, where TM's denote 3 d -transition metal elements. It shown that magnitude moments number -electrons atoms key parameters transport properties. Possible candidates showing large magnetoresistance proposed.

We conduct a theoretical study of the temperature dependence spin polarization ( P) and magnetoresistance (MR) ratio using double exchange (DE) model for ferromagnetic tunnel junctions with half-metallic systems. It is shown that strong coupling in DE plays an important role both P MR ratio; their values can be less than maximum expected systems at low temperatures, decreases more rapidly increasing temperature. The calculated results, however, indicate may still large high temperatures near Curie

Oscillations of the giant magnetoresistance (GMR) with nonmagnetic spacer layer thickness are predicted in current-perpendicular-to-plane (CPP) geometry. The methods quantum-well theory oscillatory exchange coupling applied to Kubo formula derive general selection rules for GMR oscillation periods. illustrated single-orbital tight-binding and parabolic band models. They predict that CPP oscillates not only expected Fermi-surface period but also additional periods determined by potential...

The exchange coupling (EC) observed recently in Fe/Fe${}_{3}$O${}_{4}$(001) junctions is comparable magnitude to that Co/Ru/Co trilayers and has potential applications spintronic devices. To clarify the EC mechanism, electronic magnetic states of Fe/Fe${}_{3}$O${}_{4}$ are calculated via a first-principles method by assuming four structures bcc Fe layers stacked on Fe${}_{3}$O${}_{4}$ (001) layers. We show local moment $m$ atoms increases at interface, whereas ions layer decreases inferface....

The effects of randomness on the tunnel conductance and magnetoresistance (TMR) are studied theoretically for ferromagnetic junctions. An emphasis is put a combined interfacial electronic structures metallic leads. formulated by taking into account at T =0 K zero bias limit using Kubo formula coherent potential approximation in single orbital tight-binding model. vertex correction to calculated so as satisfy current conservation law. TMR with without found depend Fermi energy E F shape...

For a magnetic multilayer system, the physical origin of difference between giant magnetoresistances for currents parallel and perpendicular to layer planes is studied. In order take into account two characteristics interfacial roughness layered structure, we adopt single-cell coherent-potential approximation. The spin-dependent resistivities are calculated by using single-band tight-binding model Kubo formalism. It shown that magnetoresistance ratio current larger than current. attributed...

We present details of the analysis effect disorder on intrinsic anomalous Hall conductivity (AHC) in a spin-polarized two-dimensional electron gas with Rashba-type spin–orbit interaction. show that AHC derived by Kubo formula vanishes when Fermi energy is larger than exchange unless lifetime spin-dependent. Results obtained numerical integration general expressions suggest could depend lifetime, contrast to previous results.

We have proposed a method for controlling the vortex chirality in squared permalloy dot by using circular Oersted field locally induced flowing DC current across small Py/Cu junctions. The reliability of control has been evaluated measuring nonlocal spin valve signal. desired obtained when injecting moderate magnitude. However, large is found to reduce reliability. Another possibility structure injection was also discussed.

We study the tunnel magnetoresistance (TMR) effect and magnetocrystalline anisotropy in a series of magnetic junctions (MTJs) with $L1_1$-ordered fcc ferromagnetic alloys MgO barrier along [111] direction. Considering (111)-oriented MTJs different $L1_1$ alloys, we calculate their TMR ratios anisotropies on basis first-principles calculations. The analysis shows that Co-based (CoNi, CoPt, CoPd) have high over 2000$\%$. These energetically favored Co-O interfaces where interfacial antibonding...

We make a theoretical study of the quantum oscillations tunneling magnetoresistance (TMR) as function spacer layer thickness. Such were recently observed in junctions with nonmagnetic metallic at barrier-electrode interface. calculate TMR ratio for disordered containing which well states are formed. A single-orbital tight-binding model, linear response theory, and coherent potential approximation used calculation. As thickness, calculated shows damped oscillation around zero single period...

Spin polarization of the tunnel conductivity has been studied for Fe/GaAs junctions with Schottky barriers. It is shown that band matching resonant interface states within barrier defines sign spin electrons transported through barrier. The results account very well experimental including tunneling photoexcited and suggest (from $\ensuremath{-}100%$ to 100%) dependent on height. They also can be controlled a bias voltage.

We analyze the effects of disorder on intrinsic anisotropic magnetoresistance (AMR) a spin-polarized two-dimensional electron gas with Rashba-type spin-orbit interaction in linear response theory. show that AMR vanishes unless lifetime is spin dependent, analogous anomalous and Hall effects, which indicates strong similarity between AMR. Furthermore, we perform numerical simulations ballistic diffusive

We develop an electron theory for the t2g electrons of Co2+ ions to clarify perpendicular magnetic anisotropy (PMA) mechanism Co-ferrite thin films by considering spin-orbit interaction (SOI) and crystal-field (CF) potentials induced local symmetry around Co global tetragonal film. Uniaxial in-plane MA constants Ku K1 at 0 K, respectively, are calculated various values SOI CF. show that reasonable parameter explain observed PMA orbital moment magnetization reduces nearly half out-of-plane...

Spin polarization of the tunnel current under finite bias voltage is studied theoretically for Fe/GaAs junctions with Schottky barriers and Fe/GaAs/Fe junctions, using a realistic tight-binding model linear response theory. Calculating spin across interface as function voltage, we show that spin-polarized resonant states within barrier significantly influence spin-dependent tunnelling. The position depends on height, can be negative rather wide range depending height. magnetoresistance also...

We experimentally demonstrated anisotropic damping of the magnetization dynamics in a highly ordered Heusler compound Co3−xFexSi (x = 1.0, 2.0, and 3.0). The field-swept ferromagnetic resonance linewidth as function resonant frequency was measured to exclude extrinsic contributions from two-magnon scattering inhomogeneous line-broadening. In L21-ordered Co2FeSi film, wide variation intrinsic Gilbert constant 0.0023 0.0061 clearly observed (111) plane, where weak uniaxial magnetic anisotropy...

We theoretically study the tunnel magnetoresistance (TMR) effect in (111)-oriented junctions Co/MgO/Co(111) and Ni/MgO/Ni(111). The Co-based junction is shown to have a TMR ratio over 2000$\%$, which one order higher than that of Ni-based one. high attributed interfacial resonance effect: $d$-$p$ antibonding states are formed close Fermi level majority-spin channel these both interfaces resonate with each other. This differs essentially from conventional coherent tunneling mechanism ratios...