Reduction of Coercivity of Fe-N Soft Magnetic Film by Heat Treatment

200 nm thick Fe-N magnetic thin films were deposited on glass substrates by RF sputtering. The as-deposited films havehigh saturation magnetization but their coercivity is also higher than what is needed Therefore it is very important to reducecoercivity.The samples were vacuum annealed at 250℃ under 12000 A/m magnetic field. When the N content was in therange of 5～7 at. pct, the thin films consisted of α'+α" after heat treatment and had excellent soft magnetic properties of4πM_s=2.4 T, H_C<80 A/m. However, the thickness of a recording head was 2 μm, and H_c increased as thickness increased.In order to reduce the H_c, the sputtering power was raised from 200 W to 1000 W to reduce the grain size. 2 μm Fe-N thin