Coupled rotators approach to the dynamics of interacting magnetic layers

Abstract

The dynamical properties of two anisotropic rotators modelling magnetic layers coupled by bilinear and biquadratic interactions terms are considered. The easy plane case is considered in detail and it is shown that the presence of the biquadratic coupling produces а sequence of bifurcations in the rotational phase spaces. In a first bifurcation a new ground state with rotators located in the easy plane and including а finite angle is generated. Hyperbolic points appear by increasing the biquadratic coupling in а second bifurcation.These hyperbolic points correspond to а nonparallel rotator configuration with rotators splitted off from the easy plane and symmetrically displaced along the transversal direction. The corresponding energy is located between the energies of the ground state and the parallel rotator configuration. Phase space portraits displaying how the stationary states are embedded in the rotational flow are shown.