Nonlinear dynamics of vortexlike domain walls in magnetic films with in-plane anisotropy in a pulsed magnetic field

The nonlinear dynamic behavior of domain walls with a vortexlike internal structure moving under the action of a pulsed magnetic field in magnetic films having an in-plane anisotropy was investigated by numerical solving the Landau-Lifshitz equations. In the framework of a two-dimensional model, the main interactions, including a dipole-dipole one (in the continuum approximation), are explicitly taken into account. Isolated and periodic field pulses with arbitrary amplitude and duration are considered. A possibility of transitions between various stationary states of wall motion induced by the pulsed fields is predicted. The transitions are shown to occur by the complicated nonlinear rearrangement of the wall structure. There are two distinctive intervals of pulse duration in which the nonlinear dynamic rearrangement radically differ. The film thickness and the magnitude of saturation induction are the main factors that have an influence on the transitions between stationary states. The periodic field pulses are established to govern the regime of wall motion, in particular, to alter the period of dynamic structure rearrangement of walls moving in a constant magnetic field. Moreover, the periodic field pulses may either completely suppress the nonstationary motion or, on the contrary, promote its development in the propulsive fields below some critical value.