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

Tht effects of N addition on the magnetic properties and structure of Fe-Hf-O sputtered films were investigated. The addition of N to Fe
_88-93
Hf
_2-3
O
_5-9
thin films was found to decrease the coercivity, H
_c
, 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, Fe
_85.1
Hf
_2.1
O
_5.5
N
_7.3
films composed of the bcc phase with fine (150 Å) grains, γ-Fe
₄
N and hafnium oxide nitride, exhibited a low coercivity of 64 A/m and a high saturation magnetization, B
_s
, of about 1.7 T even after annealing at 873K. With its high B
_s
, low H
_c
and good thermal stability, such film is expected to prove useful as a magnetic head material.