Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 28: Superconductivity: Heterostructures, Andreev Scattering, Proximity Effect, Coexistence
TT 28.6: Vortrag
Mittwoch, 25. März 2009, 17:00–17:15, HSZ 105
Spin-Supercurrents in SC/FM Heterostructures — •Roland Grein, Georgo Metalidis, Matthias Eschrig, and Gerd Schön — Institut für theoretische Festkörperphysik, Universität Karlsruhe and DFG-Center for Functional Nanostructures (CFN), D-76128 Karlsruhe, Germany
We consider a hybrid structure of a superconductor (SC) and a ferromagnet (FM) with a strong exchange field (J≈ EF). To model this system, we use an extension of the quasiclassical theory of superconductivity. Recent experimental results indicate that spin-active scattering in the interface regions between the different materials is of crucial importance for understanding the transport properties of such systems. We use a microscopic model based on wave function matching to describe this spin-active scattering. It turns out that superconducting correlations, which are transmitted through such interfaces, acquire spin-dependent scattering phases. For a Josephson junction, these scattering phases lead to a renormalization of the current-phase relation. In particular, this leads us to the prediction of a spin-supercurrent in a FM layer which is coupled to only one superconducting electrode, provided that inter-band scattering is possible at the interface and the outer surface of the FM.