Ferromagnetic resonance in a tangentially magnetized ferrite plate with normal uniaxial anisotropy and domain structure

A theoretical model is developed for the ferromagnetic resonance in a tange ntially magnetized ferrite plate with normal uniaxial anisotropy and domain structure. The model is based on the allowance for local effective fields (demagnetization fields induced by ends and lateral faces of domains and fi elds caused by the interaction of domain magnetizations through the ends an d lateral faces). It is shown that the spectrum of the ferromagnetic resona nce consists of two (as a rule, degenerate) branches. The degeneration of t he spectrum branches disappears only when the interaction of domain magneti zations through the domain ends is taken into account. Com parison of the p roposed model with experimental data revealed that the ferromagnetic-resona nce spectrum contains a frequency gap, whose parameters depend on the exter nal magnetic field. This gap is of fundamental importance for materials wit h large magnetization and small uniaxial anisotropy.