Vol.28 No.2(1) [2006]

Structural Transition and Magnetic Field Induced Strain in Ni50Mn26.5Ga23.5 Alloy

Ngo Van NONG and Michitaka OHTAKI


Polycrystalline samples of Ni50Mn26.5Ga23.5 were prepared by arc-melting method. The structural transformation from tetragonal to cubic was observed from X-ray diffraction analysis as a function of temperature in the temperature range from 100 K to 370 K. Thermal magnetization curves measured at a low magnetic field of 300 Oe showed a sharp structural transformation at TM = 260 K and a magnetic transition at Curie temperature TC = 375 K. Thermal expansions were investigated in the vicinity of TM after different cooling procedures: zero-field-cooling (ZFC) and field-cooling (FC). A magnetic-field-induced strain (MFIS) of 〜 0.2 % obtained from the difference between the ZFC and FC thermal expansions curves is remarkable.