Effects of partial substitution of Co on magnetocrystalline anisotropy and magnetic-field-induced strain in NiFeGa alloys

The effects of partial substitution of Co on magnetocrystalline anisotropy and magnetic-field-induced strain (MFIS) in Ni-Fe-Ga alloys have been investigated. To obtain a single-variant state in the martensite phase, uniaxial compressive stresses were applied to the single-crystalline specimen. The Curie temperature TC is increased up to 405 K by a partial substitution of 6 at% Co. The single-variant martensite phase in the Ni49Fe18Ga27Co6 alloy exhibits a large value of magnetocrystalline anisotropy constant K=1.2×106erg/cm3 at 300 K. Furthermore, the magnitude of the MFIS is enhanced in a wide range of temperature. Therefore, the increase of TC by the substitution of Co effectively improves the MFIS.