Regensburg 2007 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 18: Spindependent Transport II

MA 18.4: Vortrag

Mittwoch, 28. März 2007, 16:00–16:15, H22

Ab initio calculations of tunnelling anisotropic magneto-resistance (TAMR) in Fe/GaAs/Au trilayer — Voicu Popescu¹ and •Hubert Ebert² — ¹Max-Planck-Institut für Metallforschung, Heisenbergstr. 3, 70569 Stuttgart — ²Department Chemie/Physikalische Chemie, Universität München, 81377 München

We report results of calculations on the transport properties of Fe/GaAs/Au and magnetic tunnelling junctions (MTJs) that have been obtained using the tight-binding Korringa-Kohn-Rostoker Green function method in a spin-polarised fully relativistic formulation (TB-SPR-KKR).

It has been shown experimentally that the resistance of a MTJ shows a rather strong variation when its magnetisation changes the orientation, either in plane but varying the azimuthal angle, or when it is flipped from in-plane to out-of-plane.

Analogous theoretical investigations on this phenomenon, nowadays commonly termed as Tunnelling Anisotropic Magneto-resistance (TAMR) are presented for MTJs based on metallic (ferromagnetic or non-magnetic) leads. Our results show that a similar dependence is obtained also for such systems and it can be related to the spin-orbit coupling induced magnetic anisotropy at the metal/semiconductor interface. This, in turn, is shown to vary for different terminations (As or Ga) of the semiconductor. A very good qualitative agreement and a reasonable quantitative agreement is found by comparing our results with recent experimental data obtained for a Fe/GaAs/Au junction.