Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 91: [MA] Poster II
O 91.58: Poster
Freitag, 30. März 2012, 11:00–14:00, Poster A
Experimental Study of the Anisotropic Magneto-Thermopower in (113) oriented (Ga,Mn)As Thin Films — •Sibylle Meyer1, Matthias Althammer1, Lukas Dreher2, Wladimir Schoch3, Sebastian T. B. Goennenwein1, and Rudolf Gross1 — 1Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching, Germany — 2Walter Schottky Institut, Technische Universität München, Garching, Germany — 3Institut für Quantenmaterie, Universität Ulm, Ulm, Germany
In analogy to the anisotropic magnetoresistance (AMR), the thermopower of ferromagnetic materials also characteristically depends on the orientation of the magnetization vector. This anisotropic magnetothermopower (AMTP) has only scarcely been studied to date. Taking the ferromagnetic semiconductor (Ga,Mn)As with its large magneto-resistive effects as a prototype example, we have measured the evolution of both the AMR and the AMTP effects at liquid He temperatures as a function of both the orientation and the magnitude of an externally applied magnetic field. Our data show that the AMTP effect can be adequately modeled only if the symmetry of the (Ga,Mn)As crystal is explicitly taken into account. We will quantitatively compare AMR and AMTP data taken on the same (113) - oriented (Ga,Mn)As thin film with corresponding model calculations, and address the differences between the magneto-resistance and the magneto-thermopower coefficients. Financial support by DFG via SPP 1538 is gratefully acknowledged.