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MA: Fachverband Magnetismus
MA 3: Magnonics I
MA 3.8: Vortrag
Montag, 17. März 2025, 11:30–11:45, H18
Thermally Induced Demagnetizing Fields: Effective Potentials for Magnon Bose–Einstein Condensates — •Matthias R. Schweizer1, Franziska Kühn1, Victor S. L’vov2, Anna Pomyalov2,3, Georg von Freymann1,4, Burkard Hillebrands1, and Alexander A. Serga1 — 1Fachbereich Physik and Landesforschungszentrum OPTIMAS, RPTU Kaiserslautern-Landau, 67663 Kaiserslautern — 2Department of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel — 3Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 76100, Israel — 4Fraunhofer Institute for Industrial Mathematics ITWM, Fraunhofer-Platz 1, 67663 Kaiserslautern
We investigate the control of magnon Bose–Einstein condensates (mBEC) by means of reconfigurable potentials. It is shown that the localized decrease of the saturation magnetization leads to strong demagnetizing fields which elevate the resonance frequency of magnons in the mBEC state at the bottom of the spin-wave spectrum. Consequently, spatially varying magnetization and field profiles act as space-modulated potentials, determining the dynamics of the mBEC. For the experimental observation, we create reconfigurable microscopic magnetization profiles using laser heating controlled by optical wavefront modulation. Electromagnetic parametric pumping is used to increase the magnon gas density and Brillouin light scattering spectroscopy is employed to detect the mBEC dynamics. This research was supported by the DFG–TRR 173-268565370 Spin+X (Project B04).
Keywords: Bose-Einstein condensation; Magnon; Non-linear dynamics; Thermal landscapes