Structural Order, Martensitic Transformation and Magnetic Domains in Ni-Fe-Ga Shape Memory Microwire |
| L. Frolovaa, b, T. Rybac, O. Heczkob, d, T. Kmjecd, L. Feketeb, J. Kopecekb, Z. Vargovaa, c, R. Vargae
aCPM-TIP, UPJS, Park Angelinum 9, 040 01 Kosice, Slovakia bInstitute of Physics, Czech Academy of Sciences, Na Slovance 2, 18221 Prague, Czech Republic cRVmagnetics, Hodkovce 21, 044 21 Hodkovce, Slovakia dFaculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 12116 Prague, Czech Republic eDept. of Inorganic Chemistry, Faculty of Science, UPJS, Moyzesova 11, 041 54 Kosice, Slovakia |
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| We investigate Ni50Fe27Ga23 prepared as glass-coated microwires by the Taylor-Ulitovsky method. Temperature-induced martensitic transformation was observed by cooling in liquid nitrogen using optical microscope. From cubic austenite the wire transformed to heavily twinned martensitic phase. The magnetic domain structure (domain size and orientation) and its evolution were observed by magnetic force microscope at the same place after the sample was magnetized in three perpendicular directions. Surprisingly, after various magnetizing the domain structure stayed similar, and changes were minor. This probably happened due to presence of antiphase boundaries on which the domain walls are pinned. The Mössbauer spectroscopy determines the ratio between ten percent of Fe atoms in non-magnetic state and the magnetically ordered phase with L21 order which is typical for austenite. |
DOI:10.12693/APhysPolA.137.989 topics: shape memory alloys, martensitic transformation, microwire, Mössbauer spectroscopy |