Magnetostrain and magnetization of the Ni-Mn-Ga single crystal

6.2% and 5.8% giant magnetic field induced strains (MFIS) are achieved along two different orthogonal directions of a Ni/sub 50/Mn/sub 27.5/Ga/sub 22.5/ single variant sample with a switching magnetic field of 2.4 kOe. A "magnetization jump" effect is observed along an initially hard direction at the switch field of the magnetostrain. A high saturation magnetization of 71.3 emu/g and magnetocrystalline anisotropy of 1.8 /spl times/ 10/sup 5/ J/m/sup 3/ are tested in the near single variant sample. The Zeeman energy is calculated to be 1.4 /spl times/ 10/sup 5/ J/m/sup 3/, close to the mechanical deformation energy of 1.2 /spl times/ 10/sup 5/ J/m/sup 3/, which is regarded as the driving force of the twin boundaries motion. The temperature dependence of the magnetostrain is also investigated in a wide temperature range from -194 K to 290 K. Furthermore, powder X-ray diffraction pattern of Ni/sub 50/Mn/sub 27.5/Ga/sub 22.5/ demonstrates 5M tetragonal modulated martensite at room temperature.