Spontaneous magnetization and magnetic anisotropy of homogenized NiFe invar alloys

The spontaneous magnetization, M(0, T), and the magnetic anisotropy constant, K1, of f.c.c. Ni–Fe Invar alloys in the composition range from 29 to 39 at% Ni in Fe was determined from magnetization curves of (110) single crystal disks. After homogenizing, the samples show an other temperature dependence of the magnetization, M(0, T), than before. The anisotropy constants, K1, of the homogenized Invar crystals have a positive sign and a temperature dependence similar to that of Fe. Both, the spontaneous magnetization, M(0, T), and the anisotropy constant, K1, indicate that f.c.c. Ni–Fe Invar alloys behave like a ferromagnet.