Berlin 2018 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 46: Magnonics II

MA 46.3: Vortrag

Donnerstag, 15. März 2018, 15:45–16:00, H 0110

Two-dimensional wave vector resolved transport measurements of magneto-elastic bosons — •Pascal Frey, Dmytro A. Bozhko, Alexander A. Serga, and Burkard Hillebrands — Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany

Macroscopic quantum states---Bose-Einstein condensates (BECs) can be created in overpopulated gases of bosonic quasiparticles as excitons, polaritons or magnons. However, interactions between quasiparticles of a different nature, for example, between magnons and phonons in a magnetic medium, can significantly alter the properties of these gases and thus modify the condensation scenarios. Recently, we reported on the discovery of a novel condensation phenomenon mediated by the magnon-phonon interaction: an accumulation of hybrid magneto-elastic bosons. Unlike a BEC, the accumulated magneto-elastic bosons possess a nonzero group velocity, making them promising data carriers in prospective magnon spintronic circuits. Here, we present the results of two-dimensional transport measurements of magneto-elastic bosons in a single-crystal yttrium iron garnet film. Due to the strong magnetically induced anisotropy the curvature of the magnon-phonon spectrum is changed in the hybridization area and therefore we observe several spatially localized beams with different group velocities for the magnon-phonon hybrid states. The nature of the observed beams and their relations with caustic effects is discussed. This work is supported by the European Research Council within the ERC Advanced Grant "Supercurrents of Magnon Condensates for Advanced Magnonics".