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MA: Fachverband Magnetismus
MA 3: Magnonics I
MA 3.4: Vortrag
Montag, 17. März 2025, 10:15–10:30, H18
Evoution of coherence in magnonic BECs — •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 process of formation of a coherent magnon-Bose-Einstein condensate (BEC) in an over-populated, hot magnon gas has recently been intensively studied. We have already demonstrated an electromagnetic detection scheme that allows direct evaluation of the phase correlation in the BEC. We have now extended the setup to study the evolution of the phase coherence during and after the formation of a homogeneous excitation of the magnon system - a BEC. In our experiments we use a perpendicularly magnetized yttirumiron-garnet film, which is parametrically pumped. This allows us to further demonstrate that coherence arises even though the magnon gas is still heated by the pumping. Furthermore, due to the phase sensitivity of our technique, we observe the spontaneous emergence of a random phase of the BEC without any influence of external factors.
This research was funded by the Deutsche Forschungsgemeinschaft in frame of TRR 173/2*268565370 Spin+X (Project B04).
Keywords: Bose-Einstein-Condensate; Coherence; Condensates; Magnon BEC