Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 49: Symposium on Quantum Signatures in Magnetism (SYQS)
(Joint symposium of HL, MA, O and TT organized by MA)
TT 49.1: Hauptvortrag
Mittwoch, 9. März 2016, 15:00–15:30, H1
Magnonic macroscopic quantum states and supercurrents — •Burkard Hillebrands1, Dmytro A. Bozhko1,2, and Alexander A. Serga1 — 1Fachbereich Physik and Landesforschungszentrum OPTIMAS, TU Kaiserslautern, Germany — 2Graduate School Materials Science in Mainz, Germany
Magnons, the quanta of spin waves, are bosons and can form a Bose-Einstein condensate (BEC) - a spontaneous coherent ground state - established independently of the magnon excitation mechanism. The magnon BEC has zero group velocity and, thus, cannot be directly used for information transport. However, a collective motion of condensed magnons driven by a phase gradient in the condensate wavefunction - a magnon supercurrent - is a most promising candidate for the utilization of magnon macroscopic quantum phenomena at room temperature for spin information transport and processing. We report experimental evidence for the generation of a magnonic supercurrent obtained using Brillouin light scattering experiments. Here the phase gradient is induced by a thermal gradient. A rate equation model describes the experimental findings very well. Several other means to generate the needed gradient of the phase of the condensate wave function will be discussed. The work is supported by the DFG within the SFB/TR 49.