Importance of the crystalline anisotropy in commercial Ni Fe alloys

Ni-Fe alloys from 45 % to 80 % Nickel exhibit some of the most versatile magnetic properties. It is shown that the general trends of their magnetic properties can be largely interpreted in terms of the balance between the magnetocrystalline K1and the induced Ku anisotropies. Using the 55-45 Ni-Fe alloy as an example, a simple model is developed which derives the Ku and K1variations for different annealing treatments. Taking into consideration the recrystallization textures of the industrial material, an estimation of the d.c. and a.c. permeability variations with the magnetic annealing parameters is given and a good agreement with experimental results is observed.