Berlin 2015 – scientific programme

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MA: Fachverband Magnetismus

MA 20: POSTER Ib

MA 20.21: Poster

Tuesday, March 17, 2015, 09:30–13:00, Poster A

Rotation of in-plane thermal gradients in spin caloric measurements — •Oliver Reimer, Michel Bovender, Daniel Meier, Lars Helmich, Andreas Hütten, Jan-Michael Schmalhorst, Günter Reiss, and Timo Kuschel — CSMD, Physics Department, Bielefeld University

In spin caloric measurements ∇ T acts as a driving force for spin currents. A ferromagnet exposed to ∇ T in an external magnetic field generates a spin current parallel to ∇ T (longitudinal spin Seebeck effect [1]) which can be detected in materials with high spin orbit coupling (e.g. Pt) by the inverse spin Hall effect. In paramagnets the spin Nernst effect is expected to cause a transverse spin current which can induce a spin torque transfer at the interface to a magnetic material. Thus, ∇ T can be used in combination with an external magnetic field to manipulate the electric resistance in the paramagnet (spin Nernst magnetothermopower) similar to the current driven spin Hall magnetoresistance [2,3]. Since all these spin caloric effects are characterized by using a spatial fixed ∇ T varying only the base temperature and the difference of the temperatures, we introduce a new setup which allows the rotation of ∇ T. First experiments on different substrates controlled by an infrared camera show the successful rotation of ∇ T. Further calibration experiments will be presented.
[1] K. Uchida et al., Appl. Phys. Lett. 97, 172505 (2010)
[2] H. Nakayama et al., Phys. Rev. Lett. 110, 206601 (2013)
[3] M. Althammer et al., Phys. Rev. B 87, 224401 (2013)