Magnetic Properties of Fe-Si-N Films Sputtered in (Ar+N2) Plasma

Soft magnetic properties of Fe-Si alloy films sputtered in (Ar+N2) plasma are examined, and the relations between the permeability ¿eff and features of the metallurgical structure such as the lattice strain and grain size, are discussed. The total magnetic anisotropy in individual crystal grains was calculated for various Fe-Si alloys by considering the magnetoelastic energy due to the experimentally determined lattice strain. Experimentally obtained changes in ¿eff agreed well with the calculated change in total anisotropy as a function of Si concentration and N2 flow ratio. However, given the magnitude of ¿eff, this composition dependence of the ¿eff vs. N2 flow ratio is clearly a function of the grain size. It was concluded that the soft magnetic properties of Fe-Si alloy sputtered films are related to both reduction of the total anisotropy due to lattice strain from the bec to the bet structure, and also to the grain size.