Stochastic Landau-Lifshitz-Gilbert Equation with Delayed Feedback Field: Efficiency for Maintaining a UPO

Abstract

A control method to cause a stability-change between the Ising and the XY-like states in a single-domain magnetic system is studied. It is assumed that the magnetization prefers the Ising state without control due to the uniaxial anisotropy. Then, using a time-delayed feedback method and the AC field in parallel to the anisotropy axis, we consider to stabilize an oscillation of the magnetization across the equatorial plane perpendicular to the anisotropy axis (swinging motion), which possesses the XY-like symmetry. Employing a stochastic Landau-Lifshitz-Gilbert equation, we investigate effects of thermal fluctuation on the controlled state. It is suggested that the method of the delayed feedback control can maintain the controlled state with a low energy consumption.