Regensburg 2013 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 20: Transport: Spincaloric Transport (jointly with MA)

TT 20.1: Talk

Monday, March 11, 2013, 15:00–15:15, H22

Transverse magneto-thermoelectric effects in Permalloy films. — •Sasmita Srichandan, Maximilian Schmid, Michael Vogel, Christoph Strunk, and Christian Back — Institute of experimental and applied Physics, University of Regensburg, 93040 Regensburg, Germany

Thermally induced transversal magneto transport phenomena have been studied on 20 nm Py films deposited on MgO and GaAs substrates as well as on 100 nm thick SiN membranes. With an in plane thermal gradient ∇T, the transverse voltage V_T is measured on 10nm thick patterned Pt stripes on top of the Py films with respect to applied external magnetic field B at an angle θ where θ is the the angle between B and ∇T. The observed sinθcosθ dependence of V_T indicates the planar Nernst effect (PNE). Additionally we observe an asymmetry in the signal between the positive and negative B directions which is proportional to cosθ. This can be attributed to the anomalous Nernst effect (ANE) caused by a temperature gradient normal to the plane of the sample resulting from thermal radiation. The contribution of the transverse spin Seebeck effect (TSSE) which shares the same cosθ symmetry as the ANE, has been separated and it turns out to be one order smaller than reported in the literature [1]. The above measurements have also been performed on SiN membranes and they result in Nernst signals being an order higher than for bulk samples owing to the large local T gradient.

[1] K. Uchida et.al, Observation of spin Seebeck effect. Nature 455,778-781(2008).