Regensburg 2013 – scientific programme
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DF: Fachverband Dielektrische Festkörper
DF 22: Poster II
DF 22.15: Poster
Friday, March 15, 2013, 10:30–13:30, Poster D
Magnetocaloric effect in layered thin film Heusler-type materials — •Anna Möhn1,2, Anja Waske1, Niclas Teichert3, Andreas Hütten3, and Jürgen Eckert1,4 — 1IFW Dresden, Institute for Complex Materials, Dresden, Germany — 2TU Dresden, Institut für Festkörperphysik, Dresden, Germany — 3Universität Bielefeld, Fakultät für Physik, Bielefeld, Germany — 4TU Dresden, Institut für Werkstoffwissenschaft, Dresden, Germany
The magnetocaloric effect (MCE) is the increase of temperature of a material upon the application of a magnetic field and decrease when it is removed [1]. Materials which exhibit a giant MCE have a strong coupling between crystallographic structure and magnetism [2]. However, the abrupt structural change that is the origin of “giant” magnetocaloric effects, also leads to significant strain occuring in the material. The effect of strain on the magnetocaloric performance is yet unclear. To systematically study the influence of strain, we investigate a bilayer model system which introduces strain by a lattice mismatch at the interface of two different magnetocaloric materials. Experimentally we investigated sputtered thin film samples of different NiMnGa, NiMnSn and NiCoMnSn composition which show regular and inverse MCE, respectively. We determined the magnetic properties of the thin films as a function of temperature and applied magnetic field. Furthermore we determined the magnetic properties of multilayered samples which are consist of different NiMnGa and NiMnSn alloys.
[1] Giauque et. al., Phys. Rev., 43, 768 (1933)
[2] Liu et. al., Nature Mater., 11, 620 (2012)