Berlin 2012 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 20: Poster I - Biomagnetism, FePt Nanoparticles, Magnetic Particles/Clusters, Magnetic Materials, Magnetic Semiconductors, Half-metals/Oxides, Multiferroics, Topological Insulators, Spin structures/Phase transitions, Electron theory/Computational micromagnetics, Magnetic coupling phenomena/Exchange bias, Spin-dependent transport, Spin injection/spin currents, Magnetization/Demagnetization dynamics, Magnetic measurement techniques

MA 20.70: Poster

Dienstag, 27. März 2012, 12:15–15:15, Poster A

Oersted field contribution on the magnetic vortex core dynamics probed by homodyne detection — •June-Seo Kim^1,5, Martin Stärk¹, Mathias Kläui^1,5, Florian Kronast², Roland Mattheis³, Christian Ulysse⁴, and Giancarlo Faini⁴ — ¹Fachbereich Physik, Universität Konstanz, Universitätsstr. 10, D-78457 Konstanz, Germany — ²Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany — ³Institut für Photonische Technologien e.V., Jena, Germany — ⁴Phynano Team, Laboratoire de Photonique et de Nanostructures, CNRS, Marcoussis, France — ⁵Institut für Physik, Johanes Gutenberg-Universität Mainz, D-55099, Mainz, Germany

When injecting spin-polarized currents into magnetic discs, both spin torque and Oersted fields can manipulate magnetic vortex structures. The Oersted field contribution due to the inhomogeneous current distribution in the magnetic vortex core structure is experimentally determined by using a homodyne detection scheme. We find that the amplitude of the vortex core gyration increases for vortices located close to the current injection contacts due to the enhancement of the Oersted field contribution. From systematic phase measurements as a function of microwave frequency, two remarkable phenomena are observed: (i) the trajectory of the vortex core gyration is distorted by the interaction with the disc edge leading to non-linear oscillations (ii) the interplay between spin torque and Oersted field depends sensitively on the exact vortex core position.