Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 58: Spincaloric Transport I (jointly with MA)

TT 58.1: Vortrag

Mittwoch, 18. März 2015, 09:30–09:45, H 0110

The Origin of spin Seebeck effect in Iron Garnet thin films — •Er-Jia Guo¹, Andreas Kehlberger¹, Gerhard Jakob¹, Matthias B. Jungfleisch², Burkard Hillebrands², Francesco D. Coletta³, Hans Hübl³, Stephan Geprägs³, Sebastian Goennenwein³, Rudolf Gross³, and Mathias Kläui¹ — ¹Institute für Physics, Universität Mainz, 55099 Mainz, Germany — ²Fachbereich Physik, TU Kaiserslautern, 67663 Kaiserslautern, Germany — ³Walther-Meißner-Institut, Garching, Germany

The discovery of spin Seebeck effect (SSE) provides an exciting approach to generate spin currents, which are suggested to replace charge currents in order to reduce the power dissipation. However, the genuine origin of SSE is still under debate. Here, we present thickness and temperature dependences of SSE signals in Yttrium Iron Garnet (YIG) and Gadolinium Iron Garnet (GIG) films. Using Pt/YIG hybrid structures, the thickness dependence of the material shows that magnonic spin currents are the source of the SSE.[1] We find a thickness-dependent enhancement of the SSE at low temperatures, which agrees well with the thermal conductivity, implying the importance of the magnon-phonon drag. In contrast to YIG, the GIG films allow us to measure the SSE across the compensation point.[2] Two sign changes of the SSE are observed with temperature drop, revealing the SSE is not simply mirroring to the total magnetization but the magnons emitted from three interacting magnetic sub-lattices as well as the spin-mixing conductances depending on the atom type at the interface.[1]A.Kehlberger,et al.,arXiv:1306.0784 (2013)[2]S.Geprägs,et al.,arXiv:1405.4971(2014)