Dependence of magnetic properties on sputtering pressure for Fe-Al-O alloy films made by carousel-type sputtering

We have investigated the magnetic anisotropy and permeability of FeAlO films with B_s ∼ 1.8T and ρ ∼ 1 μΩm. The films were prepared using a carousel-type sputtering system. Although an aligning magnetic field to induce uniaxial magnetic anisotropy was not applied to the substrates during deposition, the FeAlO films in the as-deposited state had uniaxial magnetic anisotropy. The anisotropy strongly depends on sputtering pressure. The direction of the magnetic anisotropy shifts 90° from the rotation direction to the radial direction of the substrate holder as the sputtering pressure increases. In the pressure range of 0.3-0.4 Pa, the measured μ-f properties are largely different from the theoretical one because of magnetic anisotropy dispersion. The anisotropy dispersion can be explained by a model with two orthogonal anisotropy components.