Dresden 2017 – scientific programme
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MA: Fachverband Magnetismus
MA 67: Poster 4
MA 67.8: Poster
Friday, March 24, 2017, 09:30–13:00, P2-OG3
Non-Linear Spin-Wave Dynamics in Magnetic Vorticies — •Kai Wagner1,2, Franziska Wehrmann2, Friedrich Zahn2, Attila Kákay1, and Helmut Schultheiss1,2 — 1HZDR, Institute of Ion Beam Physics and Materials Research, Bautzner Landstraße 400, 01328 Dresden, Germany — 2TU Dresden, D-01062 Dresden, Germany
Non-linear magnetisation dynamics in micron sized Permalloy disks in the vortex state are investigated by Brillouin-Light-Scattering Microscopy and micromagnetics. To study the spectral, temporal and spatial spin-wave dynamics, a homogeneous and continuous out-of-plane pumping field is applied. For low pumping powers we observe discrete radial modes, as expected for the linear regime and homogeneity of the pumping field. However, high pumping powers lead to multiple magnon scattering, as also observed in [1] for stripe geometries. This results in complex spectra with a multitude of simultaneously occurring power dependent spin-wave frequencies, which are different from the excitation frequency. This can not be explained by simple transition rules known for spin waves in thin films. Under high pumping powers the spin-wave spectra of the vortex state in micron disks appear to be nearly continous. Hence, the conservation of energy can be easily satisfied. Therefore we believe, the corresponding rules for momentum and angular momentum conservation in these scattering processes impose sharp power dependent constraints on the possible scattering processes. [1] R. E. Camley, Phys. Rev. B 89, 214402 (2014)