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MA: Fachverband Magnetismus
MA 51: Magnetic Shape Memory Alloys (Joint Session with MM)
MA 51.9: Talk
Friday, March 20, 2015, 11:30–11:45, H 0112
Structural and magnetic phase transition in epitaxial Ni-Mn-Ga-Co films on ferroelectric substrates — •Benjamin Schleicher1,2, Robert Niemann1,2, Anett Diestel1, Ludwig Schultz1,2, and Sebastian Fähler1,2 — 1IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden, Germany — 2TU Dresden, Institute for Solid State Physics, D-01062 Dresden, Germany
To reduce today’s demand of energy for cooling applications solid-state cooling cycles relying on magnetic field induced phase transitions have been proposed. Promising materials are Heusler alloys such as Ni-Co-Mn-Ga which show an inverse magnetocaloric effect with a structural and magnetic phase transition between a ferromagnetic austenite at high T and a weak magnetic martensite at low T. Additionally to high external magnetic fields, the transformation can also be induced by the application of mechanical stress. This can be achieved by the deposition of a magnetocaloric thin film on a ferroelectric substrate. We present first results on sputter deposited epitaxial Ni-Mn-Ga-Co thin films on ferroelectric Pb(Mg1/3Nb2/3)0.72Ti0.28O3 (PMN-PT) substrates. Temperature dependent texture and magnetic measurements show the magnetic and structural phase transition in the material. By applying an electric field at the ferroelectric PMN-PT substrate we can induce the martensitic transformation in Ni-Mn-Ga-Co electrically which changes the magnetization significantly. This work is supported by DFG through SPP 1599 www.FerroicCooling.de.