Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 18: Spin-Dynamics, Magnetization Reversal I
MA 18.3: Vortrag
Dienstag, 28. März 2006, 10:45–11:00, HSZ 403
Brillouin light scattering microscopy investigations of quantized spin waves in small magnetic ring structures — •H. Schultheiss1, C. Bayer1, H.T. Nembach1, M.C. Weber1, B. Leven1, J. Podbielski2, F. Giesen2, D. Grundler2, and B. Hillebrands1 — 1Fachbereich Physik und Forschungsschwerpunkt MINAS, TU Kaiserslautern, Erwin-Schrödinger-Str. 56, 67663 Kaiserslautern, Germany — 2Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg, Germany
Spin wave quantization due to geometrical confinement and the presence of spin wave wells has been studied spatially and frequency resolved in mesoscopic magnetic ring structures. Brillouin light scattering microscopy with a spatial resolution of 300 nm allows for a local study of the spin dynamics within a single ring magnetized in the onion or the vortex state. The measured spin wave spectra do not change significantly along the ring in the vortex state, whereas in the onion state a strongly inhomogeneous internal field along the ring perimeter leads to different spin wave frequencies primarily in the pole and equatorial ring regions. Spin wave quantization in radial direction within the equatorial region of the onion state was found by comparing the experimental spectra with calculated spin wave dispersions. Moreover, effective spin wave wells caused by the inhomogeneous internal field distribution are responsible for spin wave localization in the pole region of the onion domain pattern. Hence, there is strong evidence for the coexistence of localized eigenmodes within a single microstructure due to two different quantization mechanisms.
Financial support by the DFG within the SPP 1133 and by the EC-RTN ULTRASWITCH is gratefully acknowledged.