Dresden 2011 – scientific programme

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MA: Fachverband Magnetismus

MA 49: Spin-dependent Transport/ Spin Torque

MA 49.3: Talk

Thursday, March 17, 2011, 11:15–11:30, HSZ 04

Ab initio theory of tunneling anisotropic magnetoresistance in Fe/GaAs/Ag(001) system — Rudolf Sykora and •Ilja Turek — Charles University, Faculty of Mathematics and Physics, DCMP, Prague, Czech Republic

The electronic structure and transport properties of epitaxial magnetic tunnel junctions Fe/GaAs/Ag(001) are studied theoretically by means of a first-principles tight-binding linear muffin-tin orbital (TB-LMTO) method. The effect of the spin-orbit interaction is treated as an on-site perturbation to a scalar-relativistic TB-LMTO Hamiltonian and the ballistic conductance of the system is calculated within the Kubo-Landauer formalism. Particular attention is paid to the dependence of the conductance on the orientation of magnetization direction of the Fe electrode and on the thickness of the GaAs barrier. The calculated tunneling anisotropy magnetoresistance (TAMR) ratio exhibits a non-monotonic thickness-dependence with a maximum around 8 nm of GaAs, in rough agreement with the barrier thickness used in recent experiments on TAMR in similar systems. This behavior as well as hot spots found in the k_||-resolved conductances are explained in terms of a hybridization of interface resonances formed on both sides of the junction.