Berlin 2008 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 42: Phase Transitions III

MM 42.2: Talk

Thursday, February 28, 2008, 14:15–14:30, H 0107

Microstructure and mechanical properties of sputter deposited NiMnGa magnetic shape memory alloy thin films — •Guido J. Mahnke and S. G. Mayr — 1. Physikalisches Institut, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen

While bulk magnetic shape memory alloys (MSMA) are well established - and even commerically available, miniaturization as thin functional films still remains an open issue. The relation of microstructure and mechanical properties is one of the key ingredients to understand the martensitic transformation behaviour as well as twin boundary movement in MSMA thin films. To achieve this, highly textured and epitaxial NiMnGa MSMA thin films were preprared on different substrates at variable temperature by ion beam sputtering from a multicomponent target, and charcterized with respect to phase, microstructure and growth stresses. While growth usully occurred in the austenitic phase, a twinned martensitic state usually could be obtained during cooling down, accompanied by changes in the stress state. The relation of mechanical properties and microstructure is discussed.

This project is funded by the DFG priority programme 1239, Project C4.