Magnetostatic oscillations spectrum of an ellipsoid with domain structure

A method is proposed for computing the magneto - static oscillation spectrum of an arbitrarily magnetized ferromagnetic ellipsoid both in the saturation region and the region of existence of the domain structure. The spectrum is computed for the case of a spheroidal sample of cubic ferrite monocrystal with negative first anisotropy constant magnetized perpendicular to the axis of rotation. In fields weaker than the saturation field, the computation is performed for the case of a two - phase plastic domain structure. An experimental study of the spectra of iron - yttrium garnet monocrystalline disks magnetized along [110] and cut in the plane (110) is performed in the range 400-2500 MHz. Good agreement is obtained over the entire range of field strengths studied, including in the domain structure, between the computed and experimental resonance oscillation frequencies in the (110), (220), (330), (440), (200), (210) arid (320) planes. However, a complete explanation of the low-frequency part of the experimental spectra could not be obtained, due to the inexactness of our approximation of the disk by a spheroid.