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DF: Fachverband Dielektrische Festkörper
DF 22: Poster II
DF 22.75: Poster
Freitag, 15. März 2013, 10:30–13:30, Poster D
Steady-state measurements of thermal effects in GaMnAs/ GaAs/Pt systems — •Nadezda Panarina1, Ivan Soldatov1, Christian Hess1, Rudolf Schäfer1, Sibylle Meyer2, Sebastian Gönnenwein2, Wolfgang Limmer3, and Wladimir Schoch3 — 1IFW Dresden, Dresden, Germany — 2WMI, Garching, Germany — 3Universität Ulm, Ulm, Germany
The steady-state measurements were performed on the GaAs/GaMnAs/ Pt system, where the so-called spin Seebeck effect is claimed to exist. The main principle of the steady-state technique lies in attaining and controlling thermal equilibrium and stable thermal gradient along the sample, which provides enhanced accuracy of the experimental data. It was possible to detect the transverse electric signal on the Pt strips deposited at different distances to the heater. The behavior of the detected signal (sign and value) depended strongly on the experimental details, such as position of the heater on the sample (on top or side), the range of the magnetic field sweep (varying from tens up to hundreds of mT) and temperature of measurement. Moreover, the transverse voltage was registered directly on the GaMnAs film in the same run of the experiments. This fact questions the role of Pt layers in detecting the thermal-gradient-induced signal and suggests the transverse thermopower, or planar Nernst, origin of the magneto-electric effects observed in the thin ferromagnetic film of GaMnAs.