Theory of tunneling anisotropic magnetoresistance from ab initio and model approaches

Ilja Turek

Academy of Science Czech Republic, Institute of Physics of Materials, Brno, Czech Republic

The tunneling anisotropic magnetoresistance (TAMR) in epitaxial tunnel junctions FM/I/NM, where FM denotes a ferromagnetic metallic electrode, NM a non-magnetic metallic electrode, and I an insulating (semiconducting) spacer layer, represents a phenomenon with potential applicability in spintronics. In this contribution, we present results of a first-principles study of this phenomenon for the system Fe/GaAs/Ag(001) and of a model study for the FM/I/NM junctions within a simple tight-binding approach. Our main attention will be focused on the dependence of the in-plane TAMR on the thickness of the tunnel barrier. We show that this dependence can be non-monotonic with a maximum TAMR value for intermediate barrier thicknesses. This feature is explained due to hybridized interface resonances formed at both interfaces of the junction and manifested as hot spots in k-resolved conductances.

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