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J. Phys. IV France
Volume 11, Numéro PR8, Novembre 2001
Fifth European Symposium on Martensitic Transformations and Shape Memory Alloys
Page(s) Pr8-311 - Pr8-316
Fifth European Symposium on Martensitic Transformations and Shape Memory Alloys

J. Phys. IV France 11 (2001) Pr8-311-Pr8-316

DOI: 10.1051/jp4:2001853

Large magnetic-field-induced strains in Ni-Mn-Ga alloys in rotating magnetic field

A. Sozinov1, Y. Ezer1, G. Kimmel2, P. Yakovenko3, D. Giller4, Y. Wolfus4, Y. Yeshurun4, K. Ullakko5 and V.K. Lindroos1

1  Helsinki University of Technology, Laboratory of Physical Metallurgy and Materials Science, P.O. Box 6200, 02015 Hut, Finland
2  Ben-Gurion University, Department of Materials Engineering, P.O. Box 653, Beer-Sheva, Israel
3  Institute for Metal Physics, Laboratory of Thermo-Mechanical Treatment, 003680 Kiev 142, Ukraine
4  Department of Physics, Bar-IIan University, Ramat Gan 52900, Israel
5  Helsinki University of Technology, Laboratory of Biomedical Engineering, P.O. Box 2200, 02015 Hut, Finland

A single-crystal samples of near-stoichiometric Ni2MnGa alloys with large magnetic field induced strain (MSM effect) at room temperature have been investigated. It was found that there is a reversible reorientation of easy magnetization direction and magnetic domain structure under applied magnetic field. By means of x-ray Laue diffraction method and difractometric analysis it was ascertained that these phenomena are connected with the growth of martensitic twin variant with the short crystallographic axis (c-axis) directed along the applied magnetic field. Furthermore, by means magneto-optical investigations we have found the correlation between martensitic microstructure and magnetic domain structure. The field-induced reorientation of martensite was able to change the dimensional lengths of the samples more than 4.5 %.

© EDP Sciences 2001