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MA: Fachverband Magnetismus

MA 10: Magnetization Dynamics I

MA 10.8: Talk

Monday, March 14, 2011, 16:30–16:45, HSZ 403

Imaging of the spin-wave eigenmodes of a garnet-film disc — Matthias Buchmeier, •Eric R.J. Edwards, Vladislav E. Demidov, and Sergej O. Demokritov — Institute for Applied Physics, University of Münster, Corrensstraße 2-4, 48149 Münster, Germany

Macroscopic structures based on low-loss garnet films are an ideal model system for the space-resolved investigation of spin-wave dynamics. Here we investigate the dipolar eigenmodes of a garnet-film disc by means of time- and space-resolved Faraday-effect microscopy. Thanks to the macroscopic dimensions of the studied samples, we were able to reliably image spatial profiles of the modes up to very high order. Our results show that the usual classification of eigenmodes based on their consideration as a product of standing waves in two orthogonal directions is not fully applicable in the case of in-plane magnetized disc samples. We find that the spatial distributions of the dynamic magnetization for the eigenmodes are strongly influenced by the intrinsic anisotropy of the dipolar spin-wave spectrum. Moreover, this anisotropy also leads to an appearance of a fine spatial structure, whose symmetry differs from the geometrical symmetry of the samples. These experimental results are corroborated by micromagentic simulations.