S. A. Vyatkina, R. K. Babichev, V. N. Ivanov

The dispersion characteristics of magnetostatic modes of a tangentially magnetized ferrite film with surfaces bordered on media with different permittivity have been investigated. The exact dispersion equation of electromagnetic modes of such structure, which is based on an electrodynamic approximation, has been derived. Using this equation the dispersion characteristics and the isofrequency curves of magnetostatic surface and backward volume waves in the low-wavenumber region have been calculated. The dispersion characteristics have been derived for the various values of angle between the phase velocity of electromagnetic mode and the bias field of ferrite film. It has been found that in the low-wavenumber region the magnetostatic surface and backward volume waves pass into surface and volume electromagnetic modes, which are calculated using the exact dispersion equation based on an electrodynamic approximation. When the wavenumber decreasing, the microwave field distribution in ferrite film changes: particularly, the propagation mode of surface electromagnetic waves turns into volume propagation mode. It has been shown that at given values of bias field and saturation magnetization of ferrite film, the minimum wavenumber of surface and volume electromagnetic modes, the lower frequency range limit of surface modes and the upper frequency range limit of volume modes are determined by the angle between the phase velocity of electromagnetic mode and the bias field and by the permittivity of ferrite film.