Anisotropy Dispersion and Ferromagnetic Resonance of Amorphous Soft Magnetic Films

Measurement of the anisotropy dispersion using ferromagnetic resonance at radio frequencies has been reconsidered, taking into account the skin effect in relatively thick soft magnetic films. Numerical calculations for 1 μm thick amorphous films showed that eddy current losses are comparable to the resonance absorption. The measured absorption for CoZr film is larger than the calculated absorption under a low bias field, which suggests the eddy current anomaly. In CoZr/SiO
₂
multilayered films, the anomaly is reduced. The frequency dependence of the loss part of the permeability is also discussed.