arXiv subjects

Kirill D. Belashchenko

Publications and source records attributed to Kirill D. Belashchenko.

23 records · Page 2Linked to original sources

arXiv2015

Origin of the spin reorientation transitions in (Fe$_{1-x}$Co$_{x}$)$_{2}$B alloys

Low-temperature measurements of the magnetocrystalline anisotropy energy $K$ in (Fe$_{1-x}$Co$_{x}$)$_{2}$B alloys are reported, and the origin of this anisotropy is elucidated using a first-principles electronic structure analysis. The calculated concentration dependence $K(x)$ with a maximum near $x=0.3$ and a minimum near $x=0.8$ is in excellent agreement with experiment. This dependence is traced down to spin-orbital selection rules and the filling of electronic bands with increasing electronic concentration. At the optimal Co concentration, $K$ depends strongly on the tetragonality and doubles under a modest 3% increase of the $c/a$ ratio, suggesting that the magnetocrystalline anisotropy can be further enhanced using epitaxial or chemical strain.

cond-mat.mtrl-sci↗

arXiv2013

Effects of alloying and strain on the magnetic properties of Fe$_{16}$N$_2$

The electronic structure and magnetic properties of pure and doped {Fe$_{16}$N$_2$} systems have been studied in the local-density (LDA) and quasiparticle self-consistent {\emph{GW}} approximations. The {\emph{GW}} magnetic moment of pure {Fe$_{16}$N$_2$} is somewhat larger compared to LDA but not anomalously large. The effects of doping on magnetic moment and exchange coupling were analyzed using the coherent potential approximation. The theoretical Curie temperature in pure {Fe$_{16}$N$_2$} is significantly higher than the measured value, which is attributed to the quality of available samples and the interpretation of experimental results. We found that different Fe sites contribute very differently to the magnetocrystalline anisotropy energy (MAE), which offers a way to increase MAE by small additions of Co or Ti. MAE also increases under tetragonal strain.

cond-mat.mtrl-sci↗

arXiv2009

Prediction of a spin-polarized two-dimensional electron gas at the LaAlO3/EuO(001) interface

First-principles calculations predict the existence of a spin-polarized two-dimensional electron gas (2DEG) at the LaO/EuO interface in a LaAlO3/EuO (001) heterostructure. This polar interface favors electron doping into the Eu-5d conduction bands resulting in a 2DEG formed at the interface. Due to the exchange splitting of the Eu-5d states the 2DEG is spin-polarized below the Curie temperature of EuO. The predicted mechanism for the formation of a spinpolarized 2DEG at the interface between polar and ferromagnetic insulators may provide a robust magnetism of the 2DEG which is interesting for spintronics applications.

cond-mat.mtrl-sci↗

arXiv2007

Reversal of spin polarization in Fe/GaAs (001) driven by resonant surface states: First-principles calculations

A minority-spin resonant state at the Fe/GaAs(001) interface is predicted to reverse the spin polarization with voltage bias of electrons transmitted across this interface. Using a Green's function approach within the local spin density approximation we calculate spin-dependent current in a Fe/GaAs/Cu tunnel junction as a function of applied bias voltage. We find a change in sign of the spin polarization of tunneling electrons with bias voltage due to the interface minority-spin resonance. This result explains recent experimental data on spin injection in Fe/GaAs contacts and on tunneling magnetoresistance in Fe/GaAs/Fe magnetic tunnel junctions.

cond-mat.mtrl-sci↗

arXiv2006

Tunneling anisotropic magnetoresistance driven by resonant surface states: First-principles calculations of Fe(001) surface

Fully-relativistic first-principles calculations of the Fe(001) surface demonstrate that resonant surface (interface) states may produce sizeable tunneling anisotropic magnetoresistance in magnetic tunnel junctions with a single magnetic electrode. The effect is driven by the spin-orbit coupling. It shifts the resonant surface band via the Rashba effect when the magnetization direction changes. We find that spin-flip scattering at the interface is controlled not only by the strength of the spin-orbit coupling, but depends strongly on the intrinsic width of the resonant surface states.

cond-mat.mtrl-sci↗