Nonlinear regimes of resonance precession of the magnetization in a (111) iron-garnet film

The special features of precessional motion under ferromagnetic resonance c onditions with perpendicular magnetization of the film are investigated on the basis of a numerical solution of the equations of motion of magnetizati on in a (111) type iron garnet film. Several nonlinear magnetization preces sion regimes exist for fixed values of the crystallographic and induced ani sotropies. Depending on the value of the magnetizing field and the amplitud e of the microwave field, precession occurs around the normal to the film w ith the third harmonic of the fundamental frequency making a small or large contribution to the nutation motion and with a small or large amplitude of the precession angle. Precession regimes around one of three symmetric dir ections different from the direction of the normal are possible. Narrow ran ges of the static field, where dynamical bistability and regimes with a per iod which is a multiple of the period of the microwave field are realized, exist. (C) 2000 MAIK "Nauka/Interperiodica".