Magnetic Properties of Fe-Si Sputtered Films

A detailed investigation of the relation between the differences in Fe-Si film structure governing its soft magnetic properties and film magnetic properties is discussed. The absolute values of H_c showed extreme variation with different growth conditions. The composition for which H_c was minimal was 7 to 8 wt% Si at 3.5 kV, but at 2.0 kV it was displaced to the high-Si-content side. In-plane anisotropy was independent of film growth conditions, and it was found that the films had strong uniaxial anisotropy of 1 × 10⁴ erg/cc. This fact implies that Fe-Si system sputtered film soft magnetic properties are strongly governed by magnetostriction. SEM photomicrograms of film cross sections revealed a columnar structure at 3.5 kV and tapered crystal grains with voids at 2.0 kV. Also, at 3.5 kV the (110) plane was oriented parallel to the film surface, but at 2.0 kV this orientation was disturbed and it was almost random.