Dresden 2014 – scientific programme

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MA: Fachverband Magnetismus

MA 55: Poster II

MA 55.66: Poster

Friday, April 4, 2014, 10:30–13:30, P2

Time Resolved Spin Seebeck Effect Experiments as a Probe of Magnon-Phonon Thermalization Time — Niklas Roschewsky¹, Michael Schreier¹, Akashdeep Kamra^1,2, Felix Schade¹, •Kathrin Ganzhorn¹, Sibylle Meyer¹, Hans Huebl¹, Stephan Gepraegs¹, Rudolf Gross^1,3, and Sebastian T. B. Goennenwein¹ — ¹Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching, Germany — ²Kavli Institut of Nanoscience, Delft University of Technology, Delft, The Netherlands — ³Physik-Department, TU München, Garching, Germany

We investigate magnon-phonon interaction times in the ferrimagnetic insulator yttrium iron garnet by means of time-resolved spin Seebeck effect experiments at room temperature [1]. We use an intensity modulated laser beam to dynamically generate a temperature gradient across yttrium iron garnet/normal metal thin film stacks, and record the ensuing spin Seebeck voltage. Our measurements show no intrinsic frequency dependence of the spin Seebeck voltage up to laser modulation frequencies corresponding to timescales of a few nanoseconds. These results put an upper limit to the magnon-phonon interaction time constant relevant for the spin Seebeck effect at room temperature, suggesting that small wavenumber k magnons, with magnon-phonon interaction times of a few hundred nanoseconds, do not play an important role for the spin Seebeck effect in these structures.
This work is supported by the DFG via SPP 1538 and the German Excellence Initiative via the Nanosystems Initiative Munich (NIM).
[1] N. Roschewsky et al., arXiv 1309:3986.