Effect of Hydrostatic Pressure on the Magnetocrystalline Anisotropy constant K₁ in Si-Fe and Ni

Variation of the anisotropy constant K 1 with hydrostatic pressure was determined on 1.08 wt. % Si-Fe and Ni from torque measurements under pressures up to about 5 kbar at 77, 195, 238 and 291 K. The pressure coefficient at absolute zero, (1/ K 1 (0))( Δ K 1 (0)/ Δ p ), was estimated by extrapolation as -2.1×10 -5 bar -1 for the Si-Fe and -1.4×10 -5 bar -1 for Ni. The temperature dependence of the anisotropy constant at constant volume, K 1 V , deduced with (1/ K 1 )( Δ K 1 / Δ p ) at all temperature appears to obey the ninth power of the magnetization for the Si-Fe.