INITIAL PERMEABILITY OF COMPOSITE-ANISOTROPY MULTILAYER FILMS

Initial permeabilities of composite-anisotropy multilayer films were theoretically investigated. Calculation based on the Landau-Lifshitz relation predicts that the dipole-dipole coupling between the magnetic layers works in favor of Ku (in-plane uniaxial anisotropy) in each magnetic layer and that the initial permeability increases gradually as the spacer increases in thickness along with the gradual decrease of the resonance frequency. This calculation indicates that the dipole-dipole interaction suppresses fluctuation of the initial permeability caused by thermal change of Ku. These predictions are in agreement with the experimental results.