Regensburg 2013 – scientific programme
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MA: Fachverband Magnetismus
MA 49: Magnetization Dynamics III of 3
MA 49.6: Talk
Friday, March 15, 2013, 10:45–11:00, H22
A new resonance in vortex core switching based on an interaction between gyromode and spin-waves — •Markus Sproll1, Hans Bauer2, Matthias Kammerer1, Matthias Noske1, Georg Dieterle1, Ajay Gangwar2, Markus Weigand1, Hermann Stoll1, Georg Woltersdorf2, Christian Back2, and Gisela Schütz1 — 1MPI for Intelligent Systems, Stuttgart, Germany — 2Department for Experimental Physics, University of Regensburg, Germany
The discovery of low-field vortex core (VC) switching using the sub-GHz vortex gyromode [1] as well as the much faster VC reversal by excitation of magnetostatic azimuthal spin waves in the multi-GHz range [2] mark milestones in the chapter of non-linear magnetic VC dynamics and finally lead to switching times within less than 100 ps. Here we report on surprising and unexpected new effects which have been observed by experiments at the MAXYMUS x-ray microscope at BESSY II, when the linear (sub-GHz) gyromode and circular (multi-GHz) spin waves are excited simultaneously. (i) A lowering of up to one order of magnitude of the spin wave mediated VC switching threshold is found with increasing gyromode excitation, explained by an interference of the spin waves with the excited gyromode rotation and (ii) a new additional resonance at 2.5 GHz appears which is explained by frequency doubling leading to a generation of the 'regular' 5 GHz (n=1, m=-1) spin wave mode - but only, if the sub-GHz gyromode is excited simultaneously. [1] Van Waeyenberge et al., Nature 444, 461 (2006); [2] Kammerer et al., Nature Communications 2, 279 (2011)