Effects of N Addition on the soft Magnetic Properties of Fe-Hf-O Thin Films

The effects of N addition on the magnetic properties and structure of Fe-Hf-O sputtered films were investigated. The addition of N to Fe88~93Hf2~3O5~9 thin films was found to decrease the coercivity, both in the as-deposited state and after annealing at 773K to 873K, owing to the smaller α-Fe (bcc phase) crystal grains. In particular, Fc85.1Hf2.1O5.5N7.3 films composed of the bcc phase with fine (150 Å) grains, γ-Fe4N and hafnium oxide nitride, exhibited a low coercivity of 64 A/m and a high saturation magnetization, Bs, of about 1.7 T even after annealing at 873K. With its high Bs, low and good thermal stability, such film is expected to prove useful as a magnetic head material.