Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 20: Transport: Spincaloric Transport (jointly with MA)
TT 20.4: Vortrag
Montag, 11. März 2013, 15:45–16:00, H22
Longitudinal spin Seebeck effect and anomalous Nernst effect in thin NiFe2O4/Pt films — •Daniel Meier1, Timo Kuschel1, Liming Shen2, Arunava Gupta2, Takashi Kikkawa3, Ken-ichi Uchida3, Eiji Saitoh3, Jan-Michael Schmalhorst1, and Günter Reiss1 — 1University of Bielefeld, Germany — 2University of Alabama, Tuscaloosa, USA — 3Tohoku University of Sendai, Japan
When a temperature gradient is applied along a ferromagnet/Pt system a spin current parallel to this temperature gradient is generated, which can be converted into an electromotive force (VPt) via the inverse spin Hall effect in the Pt. One can measure a voltage between the ends of the Pt film in a range of a few µV. In a ferromagnetic insulator/Pt system no regions are expected which are conductive and spin-polarized simultaneously. That is the reason why thermomagnetic effects like the anomalous Nernst effect could be neglected.
In this work we present data for the conductivity of the NiFe2O4 films and for VPt taken for NiFe2O4 films with a thin Pt film on top obtained in a setup for measurements at room temperature and in another one for investigations in a low temperature range. The NiFe2O4 films show semiconductive characteristics. Therefore, a detailed temperature dependence is studied as well as the influence of direction of an external magnetic field. The origin of the measured effects is discussed on the base of temperature dependent conductivity measurements in order to correlate the longitudinal spin Seebeck effect and the anomalous Nernst effect.