Regensburg 2013 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 22: Poster II

DF 22.71: Poster

Friday, March 15, 2013, 10:30–13:30, Poster D

Anisotropic magneto-thermopower and control of temperature gradients in (113) oriented (Ga,Mn)As thin films — •Mathias Frank¹, Sibylle Meyer¹, Lukas Dreher², Wladimir Schoch³, Rudolf Gross^1,4, and Sebastian T. B. Goennenwein¹ — ¹Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching, Germany — ²Walter Schottky Institut, Technische Universität München, Garching, Germany — ³Institut für Quantenmaterie, Universität Ulm, Ulm, Germany — ⁴Physik-Department, Technische Universität München, Garching, Germany

For caloritronic experiments, it is of crucial importance to control the direction and amplitude of temperature gradients within a given sample. We have implemented and compared different methods to apply and measure longitudinal and transverse temperature gradients in a (Ga,Mn)As thin film. We further studied the anisotropic magneto-thermopower (AMTP), i.e. the characteristic dependence of the thermopower with respect to the orientation of the magnetization vector. Our data show that the AMTP can be adequately modeled only if the symmetry of the (Ga,Mn)As crystal is explicitly taken into account. We quantitatively compare the AMTP data with the anisotropic magnetoresistance (AMR) data taken on the same (113) - oriented (Ga,Mn)As thin film and with corresponding model calculations. Moreover, we address the differences between the magneto-resistance and the magneto-thermopower coefficients. Financial support by DFG via SPP 1538 is gratefully acknowledged.