From Kinetic Instability to Bose-Einstein Condensation and Magnon Supercurrents

Alexander J. E. Kreil, Dmytro A. Bozhko, Halyna Yu. Musiienko-Shmarova, Vitaliy I. Vasyuchka, Victor S. L’vov, Anna Pomyalov, Burkard Hillebrands, and Alexander A. Serga
Phys. Rev. Lett. 121, 077203 – Published 15 August 2018

Abstract

Evolution of an overpopulated gas of magnons to a Bose-Einstein condensate and excitation of a magnon supercurrent, propelled by a phase gradient in the condensate wave function, can be observed at room temperature by means of the Brillouin light scattering spectroscopy in an yttrium iron garnet material. We study these phenomena in a wide range of external magnetic fields in order to understand their properties when externally pumped magnons are transferred towards the condensed state via two distinct channels: a multistage Kolmogorov-Zakharov cascade of the weak-wave turbulence or a one-step kinetic instability process. Our main result is that opening the kinetic instability channel leads to the formation of a much denser magnon condensate and to a stronger magnon supercurrent compared to the cascade mechanism alone.

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  • Received 28 March 2018

DOI:https://doi.org/10.1103/PhysRevLett.121.077203

© 2018 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Alexander J. E. Kreil1,*, Dmytro A. Bozhko1, Halyna Yu. Musiienko-Shmarova1, Vitaliy I. Vasyuchka1, Victor S. L’vov2, Anna Pomyalov2, Burkard Hillebrands1, and Alexander A. Serga1

  • 1Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
  • 2Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 76100, Israel

  • *kreil@rhrk.uni-kl.de

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Issue

Vol. 121, Iss. 7 — 17 August 2018

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