Effect of high uniaxial magnetocrystalline anisotropy on spectrum of hexagonal ferrite films: Static and dynamic problems

The investigation of the relation between the form of the hybrid electromagnetic-spin-wave spectrum of the hexaferrite film and the mutual orientation of the anisotropy axis and the external bias magnetic field is presented. The investigation covers the solution of both static and dynamic problems. The obtained spectrum of hybrid electromagnetic-spin waves shows a strong dependence on the mutual orientation of the anisotropy axis and the external bias magnetic field. For several special cases the hybrid waves propagating in the hexaferrite film show simultaneously dispersion properties of different types for different spin-wave modes, i.e one and the same spin-wave spectrum contains dispersion branches having different signs of phase velocity.