Magnetic Properties of Co(Fe)-based super structured films

Abstract

The change of saturation magnetostriction(λs), saturation magnetization(Bs), and soft magnetic properties(permeability μ' and coercivity Hc) were investigated for Co-based super structured films with Fe content up to 5at%. The films were prepared by using reactive RF sputtering method with N2 gas periodically mixed into Ar gas. The ratio of N2 gas partial pressure to the total gas pressure(η) was 20%, 26% and 33%. Thermal annealing of the films was performed at 515°C for an hour with a rotating magnetic fild applied in the film plane. Bs does not change within the experimental error whereas λs increases as the content of Fe increases and changes its sign from negative to positive. For the range of 86∼90at% of Co, |λs| of the films with 1∼2.5at% of Fe becomes less than 1×10-5. The anisotropy of μ', namely, the ratio of μ' along the hard axis to that along the easy axis tends to increase with Fe content. This ratio for the films prepared with η =33% is greater than that for the prepared with η =20% and 26%.