本文在理论上研究了铁磁/重金属双层薄膜结构中自旋霍尔效应自旋矩驱动的磁动力学。通过线性稳定性分析,获得了以电流和磁场为控制参数的磁性状态相图。发现通过调节电流密度和外磁场,可以获得不同的磁性状态,例如:平面内的进动态、平面内的稳定态以及双稳态。当外磁场的方向在一定的范围时,通过调节电流密度可以实现磁矩的翻转和进动。同时,通过数值求解微分方程,给出了这些磁性状态磁矩的演化轨迹。
The influence of spin Hall effect on magnetization dynamics is one of the hottest topics in spintronics. In this paper, the magnetization dynamics driven by the spin Hall effect-induced torque in a ferromagnet/heavy metal bilayer structure has been investigated theoretically. By linearizing the Landau-Lifshitz-Gilbert equation which includes the spin Hall effect torque term, and taking stability analysis, the phase diagrams in the plane defined by the current density and external magnetic field have been obtained. Under the control of the current density and external magnetic field, several magnetic states, such as in-plane stable state, in-plane precession and bistable states can be realized. With the external magnetic field oriented within a certain range, the magnetization reversal and precession can be realized through adjusting the current density. In addition, the dynamic evolutions of these magnetic states are demonstrated by solving the temporal evolutive equations numerically.