The Relation between the Magneto-Crystalline Anisotropy and the Magnetization of a Fe–Ni Invar Alloy

Magnetic field and the temperature dependences of the magnetization of a single crystal disk of Fe–Ni Invar alloy have been measured, and compared with those of the magneto-crystalline anisotropy constant, K 1 , obtained from the torque measurements. A close relationship was found between K 1 and the magnetization. The values of (d K 1 /d M ) T , obtained from the field dependence of K 1 and M , is found to be equal to (d K 1 /d M ) H , obtained from the temperature dependence of K 1 and M , even in a low temperature region. The tenth power law, proposed by Zener is only satisfied at the temperatures around 200 K.