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MA: Fachverband Magnetismus
MA 46: Magnonics II
MA 46.6: Vortrag
Donnerstag, 15. März 2018, 16:30–16:45, H 0110
Temperature dependent relaxation of magnons in yttrium iron garnet films — •Laura Mihalceanu1, Vitaliy I. Vasyuchka1, Dmytro A. Bozhko1, Thomas Langner1, Alexey Yu. Nechiporuk2, Vladislav F. Romanyuk2, Burkard Hillebrands1, and Alexander A. Serga1 — 1Fachbereich Physik and Landesforschungszentrum OPTIMAS, TU Kaiserslautern, Germany — 2Taras Shevchenko National University of Kyiv, Ukraine
The lifetime of magnons is of high relevance for the fields of magnonics, magnon spintronics and quantum computing. When approaching cryogenic temperatures, quantum phenomena in spin-wave systems pave the path towards quantum information processing. Also, an elongated magnon lifetime at low temperatures will allow to investigate the dynamics of a magnon Bose-Einstein condensates at long-time intervals. Here, the relaxation behavior of parametrically excited magnons was experimentally investigated in the temperature range from 20 K to 340 K in single crystal yttrium iron garnet (YIG) films epitaxially grown on gallium gadolinium garnet (GGG) substrates as well as in an ultrapure bulk YIG crystal. As opposed to the bulk YIG crystal in YIG films we have found a significant increase in the magnon relaxation rate below 150 K up to 10.5 times the reference value at 340 K in the entire range of probed wavenumbers. This increase is associated with rare-earth impurities contaminating the YIG samples with a slight contribution caused by coupling of spin waves to the spin system of the paramagnetic GGG substrate at the lowest temperatures. (arXiv:1711.07517) The work is supported by the DFG within the SFB/TR 49.