Berlin 2024 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 23: Magnonics II
MA 23.6: Vortrag
Mittwoch, 20. März 2024, 10:45–11:00, EB 107
Direct measurement of emergent coherence in magnonic condensates — •Malte Koster1, Matthias R. Schweizer1, Vitaliy Vasyuchka1, Dmytro Bozhko2, Burkard Hillebrands1, Mathias Weiler1, Alexander A. Serga1, and Georg von Freymann1,3 — 1Fachbereich Physik and Landesforschungszentrum OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663 Kaiserslautern, Germany — 2Department of Physics and Energy Science, University of Colorado Colorado Springs, CO 80918 USA — 3Fraunhofer Institute for Industrial Mathematics ITWM, 67663 Kaiserslautern, Germany
The formation of magnon Bose-Einstein condensates (BECs) in parametrically overpopulated magnon gas is a subject of long-standing interest to the scientific community. Recently, the possibility of electromagnetic detection of magnon condensates with a frequency resolution finer than the spectral line width of the magnon BEC has been demonstrated. Here, we present a new measurement technique for performing direct electromagnetic measurements of the magnon phases and correlation characteristics in a parametrically pumped magnon gas. In experiments with parametrically driven perpendicularly magnetized yttrium-iron-garnet films, we observe the spontaneous formation of the homogeneous Kittel mode with a random initial phase. Our measurements provide convincing experimental evidence for the spontaneous emergence of coherence in the condensate phase.
This research was funded by the Deutsche Forschungsgemeinschaft in frame of TRR 173/2*268565370 Spin+X (Project B04).
Keywords: Magnon Condensate; Coherence; Spinwave