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arXiv · 1711.07517

Temperature dependent relaxation of dipole-exchange magnons in yttrium iron garnet films

Laura Mihalceanu·Vitaliy I. Vasyuchka·Dmytro A. Bozhko·Thomas Langner·Alexey Yu. Nechiporuk·Vladyslav F. Romanyuk·Burkard Hillebrands·Alexander A. Serga
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Abstract

Low energy consumption enabled by charge-free information transport, which is free from ohmic heating, and the ability to process phase-encoded data by nanometer-sized interference devices at GHz and THz frequencies are just a few benefits of spin-wave-based technologies. Moreover, when approaching cryogenic temperatures, quantum phenomena in spin-wave systems pave the path towards quantum information processing. In view of these applications, the lifetime of magnons$-$spin-wave quanta$-$is of high relevance for the fields of magnonics, magnon spintronics and quantum computing. Here, the relaxation behavior of parametrically excited magnons having wavenumbers from zero up to $6\cdot 10^5 \mathrm{rad~cm}^{-1}$ 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 a bulk YIG crystal$-$the magnonic materials featuring the lowest magnetic damping known so far. 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.

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Laura Mihalceanu, Vitaliy I. Vasyuchka, Dmytro A. Bozhko, Thomas Langner, Alexey Yu. Nechiporuk, Vladyslav F. Romanyuk, Burkard Hillebrands, Alexander A. Serga. 2017-11-20. Temperature dependent relaxation of dipole-exchange magnons in yttrium iron garnet films. https://doi.org/10.1103/physrevb.97.214405

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