Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 84: Focus Session: Nanoscopic Superconducting Heterostructures
TT 84.1: Invited Talk
Thursday, March 19, 2015, 09:30–10:00, H 0104
Creating and Manipulating Nonequilibrium Spins in Nanoscale Superconductors — Michael J. Wolf1, Florian Hübler1,2, Stefan Kolenda1, Christoph Sürgers3, Gerda Fischer3, Hilbert von Löhneysen2,3, and •Detlef Beckmann1 — 1Institut für Nanotechnologie, Karlsruher Institut für Technologie — 2Institut für Festkörperphysik, Karlsruher Institut für Technologie — 3Physikalisches Institut, Karlsruher Institut für Technologie
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, we find signatures of spin transport over distances of several µm [1], exceeding other length scales such as the coherence length, the normal-state spin-diffusion length, and the charge-imbalance length [2]. Using a combination of ferromagnetic and normal-metal contacts, we demonstrate spin injection from a normal metal, and show a complete separation of charge and spin imbalance [3]. An exchange splitting induced by the ferromagnetic insulator europium sulfide enables spin transport at very small applied magnetic fields, and therefore paves the way to manipulating spin currents by local exchange fields [4].
[1] F. Hübler et al., Phys. Rev. Lett. 109, 207001 (2012)
[2] F. Hübler et al., Phys. Rev. B 81, 184524 (2010)
[3] M. J. Wolf et al., Phys. Rev. B 87, 024517 (2013)
[4] M. J. Wolf et al., Phys. Rev. B 90, 144509 (2014)