Regensburg 2016 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 24: Topical session: Caloric Effects in ferroic materials II - Methods and Applications

MM 24.4: Vortrag

Dienstag, 8. März 2016, 12:45–13:00, H53

In-situ synchrotron XRD investigation of the structural phase transition in epitaxial Ni-Mn-Ga-Co thin films on ferroelectric substrates — •Benjamin Schleicher^1,2, Stefan Schwabe¹, Robert Niemann^1,2, Anett Diestel¹, Anja Waske¹, Ruben Hühne¹, Peter Walter^3,4, Ludwig Schultz^1,2, Kornelius Nielsch¹, and Sebastian Fähler^1,2 — ¹IFW Dresden, P.O. Box 270116, D-01171 Dresden, Germany — ²TU Dresden, Institute for Solid State Physics, D-01062 Dresden, Germany — ³Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, D-22607 Hamburg, Germany — ⁴2^nd Institute of Physics B and JARA-FIT, RWTH Aachen University, D-52047 Aachen, Germany

For solid-state refrigeration, the phase transition in Ni-Mn-Ga-Co can not only be influenced by magnetic fields, but also by mechanical stress. This can be achieved by straining an epitaxial magnetocaloric thin film via a ferroelectric substrate. We investigated sputter deposited epitaxial Ni-Mn-Ga-Co thin films on ferroelectric Pb(Mg_1/3Nb_2/3)_0.72Ti_0.28O₃ (PMN-PT) substrates. Temperature dependent texture and magnetic measurements show the structural and magnetic phase transition in the material. In-situ synchrotron XRD measurements on the P02.1 beamline at PETRA III (DESY, Hamburg) have been used to demonstrate the influence of mechanical stress on the phase transition by in-situ application of an electric voltage to the multiferroic stack and a temperature-strain phase diagram was obtained. Funded by DFG through SPP 1599 www.FerroicCooling.de.