THEORY OF NONLINEAR FERROMAGNETIC-RESONANCE IN THE SAMPLES WITH MAGNETOSTATIC AND EXCHANGE BOUNDARY-CONDITIONS IMPOSED

General theory of nonlinear ferromagnetic resonance is presented for s amples with the usual magnetostatic and exchange boundary conditions i mposed at the sample surface. In such samples the Suhl instabilities a nd other nonlinear effects occur due to nonlinear interactions of magn etostatic or dipole-exchange modes. All relevant types of interactions are included in the Hamiltonian: with the pumping field, three- and f our-mode ones. Analytic calculation of the Suhl thresholds in the thre e possible types of instabilities in perpendicular and parallel pumpin g is performed for the sample in the shape of a thin slab.