Regensburg 2019 – wissenschaftliches Programm
MA 4.11: Vortrag
Montag, 1. April 2019, 12:15–12:30, H52
Nonmagnet-Barrier Interface Drives Tunnelling Anisotropic Magnetoresistance — •Philipp Risius, Carsten Mahr, Michael Czerner, and Christian Heiliger — Institut für theoretische Physik, Justus-Liebig-Universität Gießen, Gießen
Tunnel junctions with a single ferromagnetic layer (semi-magnetic tunnel junction, SMTJ) may show magnetoresistance if spin-orbit interaction (SOI) is present in the ferromagnetic layer. This effect is called tunneling anisotropic magnetoresistance (TAMR). SMTJs employing a thin iron layer, magnesium oxide as tunnel barrier, and vanadium as leads (V|Fe|MgO|V) show TAMR and an appreciable spin-orbit torque at room temperature . We investigate the origins of TAMR by calculating the transport across SMTJs from first principles, and investigate the effect of disorder at the Fe|V interface. For this, we utilized a fully relativistic Korringa-Kohn-Rostoker non-equilibrium Green’s function method including the coherent potential approximation and vertex corrections . We recovered the k-resolved transmission and temperature-dependent TAMR ratio. Crucially, we show that the effect depends on a subtle interplay of the interfaces on both sides of the tunnel barrier, and that the magnitude of SOI at the ferromagnet-insulator interface can even be secondary to the choice of materials.
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 C. Franz, M. Czerner and C. Heiliger, J. Phys. Condens. Matter 25, 425301 (2013).