Temperature Variation Of Structure Research Articles

Temperature variation of structure and magnetic properties of Ni–Mn–Ga magnetic shape memory alloys

When cooling from high temperature, the material of composition Ni 48.5Mn 30.3Ga 21.2 undergoes several magnetic and structural transitions. The phases are, at high temperature austenitic cubic L2 1 phase; at 297 K 5-layered modulated tetragonal martensite; and below 210 K non-modulated tetragonal martensitic phase with c/ a larger than unity. Five-layered martensite exhibits giant field-induced strain of about 6% (magnetic shape memory (MSM) effect). The mechanism of the MSM effect was substantiated by simultaneous measurement of the strain and magnetization.