Regensburg 2013 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 50: Poster II
MA 50.70: Poster
Freitag, 15. März 2013, 10:30–13:30, Poster D
In search of spin caloric effects in thin permalloy films using different setups for transverse spin Seebeck effect measurements — •Timo Kuschel1, Daniel Meier1, Takashi Kikkawa2, Ken-ichi Uchida2, Eiji Saitoh2, Jan-Michael Schmalhorst1, and Günter Reiss1 — 1University of Bielefeld, Germany — 2Tohoku University of Sendai, Japan
In spin caloritronics the spin Seebeck effect (SSE) (generation of a spin current by a temperature gradient) plays an important role. After the original observation in thin permalloy films on sapphire substrates in the transverse geometry (TSSE) in 2008 many scientific groups tried to measure the TSSE on different materials. Often an additional out-of-plane temperature gradient generates an anomalous Nernst effect (ANE) which contributes to the measured signal.
We built up a setup for TSSE measurements and investigated thin permalloy films on sapphire and MgO substrates. While our measurements reveal a symmetric contribution concerning the external magnetic field due to the anisotropic thermopower (planar Nernst effect), an additional asymmetric contribution due to the TSSE or ANE is not observed in most cases. For comparison we used the original setup in Japan and obtained different results for the same samples. An asymmetric contribution due to the TSSE or ANE is now contributing for nearly every sample. This inconsistency is discussed in the context of setup differences and probable out-of-plane temperature gradients.