Microwave magnetic properties of the oriented CoIr soft magnetic film with negative magnetocrystalline anisotropy

The natural resonance frequency of the oriented soft magnetic thin film with in-plane uniaxial anisotropy and negative magnetocrystalline anisotropy (Kugrain) was investigated in hcp structure of Co80Ir20 film with the c  -axis perpendicular to the film plane. As the out-of-plane anisotropy field contained the field produced by negative Kugrain besides the demagnetization field, the natural resonance frequency was enhanced dramatically compared with the conventional soft magnetic film without magnetocrystalline anisotropy. Through solving the equation of magnetization precession, the initial permeability of this kind of film was shown to be unrelated to the negative Kugrain and yet determined by the in-plane uniaxial anisotropy field and the saturation magnetization of the film.