论文标题
垂直磁性隧道连接的自旋转移切换中的微磁性不稳定性
Micromagnetic instabilities in spin-transfer switching of perpendicular magnetic tunnel junctions
论文作者
论文摘要
微磁性不稳定性和非均匀磁力化状态在自旋转移诱导纳米尺度磁元素的转换中起重要作用。在这里，我们模拟了域壁介导的开关动力学，以垂直磁性磁性隧道连接纳米柱。我们表明，域壁表面张力总是导致与连接磁盘形状相关的磁化振荡和不稳定性。开发了一个集体坐标模型，该模型捕获了这些不稳定性的各个方面，并说明了它们的身体起源。将模型结果与微磁模拟的结果进行比较。发现开关动力学对域壁位置和相位非常敏感，这表征了磁盘平面中磁化的角度。在存在自旋扭矩的情况下，这种灵敏度降低了，而置换域壁所需的自旋电流可能远小于从均匀磁化状态切换的阈值电流。该模型的预测是转换过程中频率增加的电导振荡。
Micromagnetic instabilities and non-uniform magnetization states play a significant role in spin transfer induced switching of nanometer scale magnetic elements. Here we model domain wall mediated switching dynamics in perpendicularly magnetized magnetic tunnel junction nanopillars. We show that domain wall surface tension always leads to magnetization oscillations and instabilities associated with the disk shape of the junction. A collective coordinate model is developed that captures aspects of these instabilities and illustrates their physical origin. Model results are compared to those of micromagnetic simulations. The switching dynamics is found to be very sensitive to the domain wall position and phase, which characterizes the angle of the magnetization in the disk plane. This sensitivity is reduced in the presence of spin torques and the spin current needed to displace a domain wall can be far less than the threshold current for switching from a uniformly magnetized state. A prediction of this model is conductance oscillations of increasing frequency during the switching process.
