Institute of Assembly Technology and Robotics Research Publications
Crystal Quality Boosts Responsiveness of Magnetic Shape Memory Single Crystals

Crystal Quality Boosts Responsiveness of Magnetic Shape Memory Single Crystals

Categories Zeitschriften/Aufsätze (reviewed)
Year 2008
Authors Rolfs, K.; Mecklenburg, A.; Guldbakke, J.-M.; Wimpory, R.; Raatz, A.; Hesselbach, J.; Schneider, R. C.
Published in Journal of Magnetism and Magnetic Materials, Elsevier, 2008, pp. 1112-1117
Description

Magnetic shape memory alloys are promising materials to replace giant magnetostrictive materials and piezoelectrical ceramics in actuating devices due to the large magnetically induced strains. Ni–Mn–Ga is the most intense studied system due to its relatively high operational temperatures and the huge magnetically induced strains reported. Up to now the application of these materials is still limited by the operational temperature range. Additionally twin boundary mobility suffers from structural defects increasing the magnetic fields needed for significant and reproducible strains. The sample quality is affected by crystal inhomogeneity, porosity and impurities. Here new results are reported for the Ni–Mn–Ga class based on a set of single crystals grown by the SLARE method, recently developed by Mecklenburg et al. Single crystalline samples of of tetragonal martensitic structure exhibit a magnetic field induced strain of more than 4% below 170 mT and 6.5% at only 340 mT. Furthermore the operational temperature regimen could be expanded up to 65 °C.

ISSN 0304-8853
DOI 10.1016/j.jmmm.2008.10.023