The Stability of Magnetic-Field-Induced Strain in a NiMnGa Ferromagnetic Shape Memory Alloy
The stability of magnetic field induced strain (MFIS) in Ni52Mn24Ga24 single crystal under temperature and magnetic field cycling is investigated and the corresponding micro-mechanism is also discussed. It shows that the saturated MFIS is very sensitive to temperature. Below martensitic transformation temperature(Tm), with increasing temperature, the saturated MFIS increases almost linearly. Besides, the saturated MFIS initially decreases with increasing the field cycling number less than four times, then does not change with further increasing the number of field cycles. The decrease of saturated MFIS can be attributed to the decrease of twin boundary mobility, which is related to the crystal defect introduced by immigration of twin boundary under field cycling.
Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie
F. Chen et al., "The Stability of Magnetic-Field-Induced Strain in a NiMnGa Ferromagnetic Shape Memory Alloy", Materials Science Forum, Vols. 475-479, pp. 2025-2028, 2005