Berlin 2012 – scientific programme
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MA: Fachverband Magnetismus
MA 34: Magnetization / Demagnetization Dynamics III
MA 34.1: Talk
Wednesday, March 28, 2012, 15:00–15:15, H 1012
Magnetic vortex core reversal by excitation of spin waves — •Hermann Stoll1, Matthias Kammerer1, Markus Weigand1, Michael Curcic1, Matthias Noske1, Markus Sproll1, Arne Vansteenkiste2, Bartel Van Waeyenberge2, Georg Woltersdorf3, Christian H. Back3, and Gisela Schütz1 — 1MPI for Intelligent Systems, Stuttgart (formerly MPI for Metals Research) — 2Department of Solid State Science, Ghent University, Belgium — 3Department of Physics, Regensburg University
Vortex structures possess azimuthal spin wave modes showing much higher eigenfrequencies than the vortex gyromode. Recently we could image by time-resolved scanning transmission X-ray microscopy vortex core reversal by exciting spin wave eigenmodes with rotating multi-GHz magnetic fields [1], much faster than by excitation of the sub-GHz vortex gyromode as demonstrated before. The vortex core polarization can be switched unidirectionally, either to up or down, as excitation only takes place when the sense of rotation of the external field and the spin wave mode are the same. These experimental results are in good agreement with our micromagnetic simulations [1], which clearly show: (i) the selection rules for this vortex core reversal process, (ii) the creation of a VA pair which is also essential for spin wave mediated vortex core reversal, (iii) asymmetries in vortex - spin wave interaction, caused by the gyrofield of the moving vortex, when spin waves with opposite rotation senses are excited. Limitations of the switching times for spin wave mediated vortex core reversal will be discussed.
[1] M. Kammerer et al., Nature Communications 2, 279 (2011)