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MA: Fachverband Magnetismus
MA 19: Spin-Dynamics/Switching I
MA 19.3: Vortrag
Mittwoch, 28. März 2007, 15:45–16:00, H23
Detecting Vortex Chirality by Ferromagnetic Eigenmodes in Mesoscopic Rings — •Fabian Giesen1,2,3, Jan Podbielski1, Bernhard Botters1,4, and Dirk Grundler1,4 — 1Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, 20355 Hamburg — 2Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2J7 Canada — 3Max-Born-Institut für ür Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2 A , 12489 Berlin — 4Lehrstuhl für Experimentalphysik E10, TU München, James-Franck-Straße 1, 85747 Garching
Using broadband ferromagnetic resonance and specially engineered asymmetries in permalloy rings we are able to detect the statistics of chirality of the vortex state in an array of rings. We make use of localized modes in the rings which serve as a probe for the local magnetization direction. We find that the asymmetry suppresses the usual domain wall propagation reversal process, which in the case of concentric rings, leads to a distribution of vortex chirality directions. Instead the reversal takes place through a buckling of the magnetization in the wide ring arm. This arm always switches first and leads to a control of the vortex chirality with a fidelity of better than 97%. The chirality ξ=±1 can be selected by the inital external field direction.
The research was funded by BMBF Spintronic 12N8283, iCore and CIAR.