自旋转移矩驱动的磁化翻转理论研究

Theoretical Study on Magnetization Reversal Induced by Spin-transfer Torque

采用宏自旋模型和Landau-Lifshitz-Gilbert-Slonczewski(LLGS)方程讨论了垂直磁化隧道结的磁化翻转,结果表明:(1)减小隧道结自由层的厚度可以加快磁化翻转;(2)通过增加外电场,可以降低自由层的磁各向异性,从而加快磁化翻转速度;(3)双界面五层膜隧道结可以增加自旋极化电流,从而加快磁化翻转速度。上述理论分析对于提高自旋转移矩磁随机存储器的性能有重要意义。

The magnetization reversal of magnetic tunnel junctions(MTJs)with particular magnetization was discussed by using macro-spin model and LLGS equation.The results show that,(1)the magnetization reversal would speed up by reducing free layer thickness of MTJs;(2)the magnetization reversal speed would be accelerated by applying an external electrical field to lower the perpendicular magnetic anisotropy of a free layer;(3)the magnetic switching would also be faster in the pentalayer MTJs with dual interfaces due to spin-polarized current increase in this kind of MTJs.The above theoretical analysis is of great significance to improve the performance of spintransfer-torque magnetic random access memory.