Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 64: Superconductivity: Heterostructures, Andreev Scattering, Vortex Physics
TT 64.1: Vortrag
Donnerstag, 14. März 2013, 15:00–15:15, H21
Spin injection from a normal metal into a mesoscopic superconductor — •Michael J. Wolf1, Florian Hübler1,2,3, Stefan Kolenda1, Hilbert v. Löhneysen2,3,4, and Detlef Beckmann1,2 — 1Institut für Nanotechnologie, KIT, 76021 Karlsruhe, Germany — 2Center for Functional Nanostructures, KIT, 76131 Karlsruhe, Germany — 3Institut für Festkörperphysik, KIT, 76021 Karlsruhe, Germany — 4Physikalisches Institut, KIT, 76128 Karlsruhe, Germany
We report on nonlocal transport in superconductor hybrid structures, with ferromagnetic as well as normal-metal tunnel junctions attached to the superconductor.
In the presence of a strong Zeeman splitting of the density of states, both charge and spin imbalance is injected into the superconductor.
While previous experiments [1,2] demonstrated spin injection from ferromagnetic electrodes, we show that spin imbalance is also created for normal-metal injector contacts.
Using the combination of ferromagnetic and normal-metal detectors allows us to directly discriminate between charge and spin injection, and demonstrate a complete separation of charge and spin imbalance.
The relaxation length of the spin imbalance is of the order of several µm and is found to increase with a magnetic field, but is independent of temperature.
We further discuss possible relaxation mechanisms for the explanation of the spin relaxation length.
[1] F. Hübler et al., Phys. Rev. Lett. 109, 207001 (2012)
C. H. L. Quay et al., arXiv:1208.0500