电流驱动磁化翻转中的热效应

Thermal effect in current induced magnetic switching

从理论上研究了电流驱动磁开关中的热效应,在Neel-Brown弛豫时间理论和Li等的有效温度的工作基础上作了改进.在对称系综模型的Landau-Lifshitz-Gilbert和Fokker-Planck方程的基础上,分析了电流驱动磁动力学开关过程和电流引起磁势能的变化,提出一个新的电流感应磁势垒降低模型.新模型是非线性的,与Li等的有效温度模型不同.在此模型的基础上,讨论了开关临界电流对温度、开关时间的依赖关系,理论与实验相符合.对电流引起的样品温升的实验曲线进行了修正,实验结果与文中的非线性势垒降低模型一致.此外由实验确定了磁开关的本征开关电流Ic0、尝试时间τ0和本征势垒Eb0.

Based on the Neel-Brown relaxation time theory and the effective temperature model proposed by Li et al.,the thermal effect in current induced magnetic spin torque switching is theoretically studied.On the basis of Landau-Lifshitz-Gilbert equation and Fokker-Planck equation,through analyzing the current induced magnetic switching and potential change,a new model to explain the potential barrier reducing is proposed.Different from Li s model,this model is nonlinear.The model is used to discuss the relation between temperature, switching time and critical current. For the current induced temperature rise, our model does accord with the experiment well. The method for determining the intrinsic switch electric current, testing time and intrinsic potential barrier in magnetic switching is also proposed.