Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 87: Focus Session: Unconventional Spin Structures (organized by MA)
TT 87.6: Topical Talk
Donnerstag, 3. April 2014, 12:15–12:45, BEY 118
Magnetic Vortex Core Reversal by Excitation of Spin Waves — •Hermann Stoll1, Matthias Kammerer1, Matthias Noske1, Markus Sproll1, Georg Dieterle1, Ajay Gangwar1,2, Markus Weigand1, Manfred Fähnle1, Georg Woltersdorf2, Christian H. Back2, and Gisela Schütz1 — 1MPI for Intelligent Systems, Stuttgart, Germany — 2University of Regensburg, Germany
Essential progress in the understanding of nonlinear magnetic vortex dynamics was achieved when low-field vortex core reversal by (sub-GHz) excitation of the vortex gyromode was observed using time-resolved scanning transmission X-ray microscopy [1]. This switching scheme, based on the creation and subsequent annihilation of a vortex-antivortex pair [1,2], has been proved to be universal and independent of the type of excitation, e.g., pulsed magnetic fields or spin transfer torque (STT).
Magnetic vortex structures possess azimuthal spin wave modes showing eigenfrequencies in the multi-GHz range. We could demonstrate [3-5] by experiments and micromagnetic simulations that even much faster unidirectional vortex core reversal can be achieved by exciting these spin wave modes with (multi-GHz) rotating magnetic fields. In that way we have been able to switch vortex cores selectively within less than 100 ps.
[1] B. Van Waeyenberge et al., Nature 444, 462 (2006) [2] A. Vansteenkiste et al., Nature Physics 5, 332 (2009) [3] M. Kammerer et al., Nature Communications 2, 279 (2011) [4] M. Kammerer et al., PRB 86, 134426 (2012) [5] M. Kammerer et al., APL 102, 012404 (2013)