Regular and Stochastic Nonlinear Dynamics of Magnetization in an Exchange-Coupled Multilayer Structure

摘要

Various oscillating systems with both stochastic and regular dynamical regimes have attracted wide attention in recent years [1]. Among the most studied of such systems are magnetically ordered structures whose dynamics is associated with the precession motion of magnetization and is generally described by the Lan-dau-Lifshitz nonlinear equations [2, 3]. Of great interest today are multilayer exchange-coupled structures, where giant rnagnetoresistive and magnetooptical effects have been discovered [4-6]. The existence of static and dynamical bistable states characteristic of a magnetic subsystem is substantial for the practical use of such structures [7, 8]. The behavior of the magnetic subsystem near these states determines the features of the self-organization of magnetization, which proceeds in external magnetic fields [9]. In this work, we analyze dynamical regimes of the magnetization of a multilayer nanostructure with an antiferromagnetic interlayer exchange coupling that permits the realization of various equilibrium states [10]. We show that there are narrow frequency bands where self-sustained oscillations transform to stochastic oscillations of magnetization.