Temperature Dependence of Anisotropy and Saturation Magnetization in Iron and Iron-Silicon Alloys

The temperature dependence of the magnetocrystalline anisotropy constant $K_1$ and of the saturation magnetization have been measured from 77 to 575°K on single-crystal samples of iron, 3.2% silicon-iron, and 5.1% silicon-iron. For iron and 3.2% Si-Fe, the anisotropy decreases as the third or fourth power of the magnetization at low temperatures; this increases to approximately the ninth power at high temperatures. The anisotropy of 5.1% Si-Fe decreases as the seventh or eighth power of the magnetization at low temperatures, and as the ninth power at high temperature.