The influence of the alternating magnetic field on the equilibrium position dynamics of the magnetization precession in an anisotropic magnetic film

This work deals with the features of dynamics of the second order magnetization vector precession excited by a circularly polarized alternating magnetic field in a normally magnetized ferrite plate. Processes of parametric excitation and related losses can be prevented by choosing the normal magnetized plate geometry. The system of the equations was solved numerically by the RungeKutta 7 8 orders method with the integration control at every step length. The precession modes of the magnetization vector, ampli tudefrequency characteristics of the equilibrium position and parameters of the successive transition between them were determined. Parametric portraits for the precession modes were constructed. Four regimes of the second order precession that substitute one another in case of the amplitude of the alternating field being increased have also been found. There are the following regimes: regime A small amplitude circular precession; regime B precession of equilibrium position without encircling the center; regime C precession of equilibrium position with encircling the center; regime D damped precession of equilibrium position. The features of the distribution of instability regions in various modes are revealed. The dependences of the precession frequency on the magnetic field amplitude are determined. The precession frequency of the equilibrium position in creases with increasing amplitude of the alternating field up to 800 Oe. After that, the frequency begins to decrease monotonously to the amplitude field of 1050 Oe. However, the precession frequency of the equilibrium position of the magnetization vector in creases in the range of amplitudes of the alternating field 1100 ≤ h0 ≤ 1650)$ Oe. This phenomenon can be explained by occurrence of the oscillations with a combination frequencies caused by the instability region at the doubled disturbance frequency ω = 2·ω0.