Berlin 2012 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 52: Poster II - Magnetic Heusler compounds, Magnetic shape memory alloys, Thin Films, Micro-/Nano-structured magnetic materials, Graphene, Spins in organics, Magnetic imaging, Surface Magnetism, Spin excitations/Torque, Spincaloric transport

MA 52.58: 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.