Regensburg 2013 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 16: Poster I
MA 16.55: Poster
Dienstag, 12. März 2013, 10:30–13:30, Poster D
Martensitic Transition in Ni-Mn-Ga/Ni-Mn-Sn Multilayer Thin Films — •Niclas Teichert1, Anna Möhn2,3, Anja Waske3, Biswanath Dutta4, Tilmann Hickel4, and Andreas Hütten1 — 1Department of Physics, Thin Films and Physics of Nanostructures, Bielefeld University, 33615 Bielefeld, Germany — 2IFW Dresden, Institute for Complex Materials, 01069 Dresden, Germany — 3TU Dresden, Institut für Festkörperphysik, 01062 Dresden, Germany — 4Max-Planck-Institut für Eisenforschung GmbH, 40237, Düsseldorf, Germany
Both Ni-Mn-Sn and Ni-Mn-Ga are ferromagnetic shape-memory Heusler alloys and show a martensitic transition accompanied by a magnetocaloric effect (MCE) in a certain composition range. The MCE is inverse in Ni-Mn-Sn and conventional in Ni-Mn-Ga. We want to achieve a coupling of both effects in multilayer thin films in order to enhance the MCE. This approach gives rise to additional interface entropy, magnetic interaction across the interfaces and lateral strain due to the lattice mismatch.
We prepared different epitaxial Ni-Mn-Ga/Ni-Mn-Sn multilayer thin films on heated MgO(001) substrates by magnetron sputtering. The number of layers as well as the layer thickness is varied to study the effects of interfaces, strain and interdiffusion between the layers on the martensitic transition. This is done by temperature dependent resistivity and magnetoresistance measurements, magnetic measurments, X-Ray diffraction and Auger electron spectroscopy.