Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 28: Optical properties
HL 28.8: Vortrag
Mittwoch, 28. März 2007, 16:00–16:15, H14
Fringe field induced modification of the coherent spin dynamics in GaAs — Patric E. Hohage1, •Jörg Nannen1, Tilmar Kümmell1, Gerd Bacher1, Dirk Reuter2, and Andreas D. Wieck2 — 1Werkstoffe der Elektrotechnik, University Duisburg-Essen, Bismarckstr. 81, 47057 Duisburg, Germany — 2Angewandte Festkörperphysik, Ruhr-University Bochum, Universitätsstr. 150, 44780 Bochum, Germany
Ferromagnet-semiconductor hybrids are promising candidates for spin manipulation in potential spintronic devices. Using time-resolved Kerr rotation, we studied the coherent evolution of electron spin states in both ferromagnet-GaAs hybrids and pure n-GaAs bulk crystals. The experiments on n-GaAs allow us to extract the oscillation frequency of the electron spin beats up to room temperature, which is controlled by the electron g factor and the external magnetic field. By defining lithographically microscale ferromagnets on top of the semiconductor, we are able to locally manipulate the oscillation frequency of the electron spins due to the influence of the additional ferromagnetic fringe field. Compared to reference measurements in bulk GaAs, we find an enhancement of the electron spin precession frequency e.g. of 1.1 GHz at an external magnetic field of 1 T by using Co wires with a width of 6 µm and an interwire distance of 1 µm. Thus, even tiny fringe fields in the order of several mT result in a measurable change of the precession frequency.