自旋极化电流驱动下磁涡旋的旋转回归运动和手征性反转

将方向为（-1,1,-1）的3个自旋极化电流通入纳米盘, 用OOMMF(object oriented micromagnetic framework）软件分析自旋极化电流大小和位置分布对磁涡旋动力学行为的影响. 结果表明： 磁涡旋核做旋转回归运动时, 最大速度在轨迹上的位置相对固定, 利用该性质， 可在最大速度处引入缺陷, 使磁涡旋核运动到缺陷处被钉扎并发生反转, 从而实现磁涡旋核极性的可控反转； 通过改变极化电流的大小或位置, 可调节磁涡旋核旋转回归运动频率的大小； 在高电流密度区域, 可实现磁涡旋手征性反转, 且反转时间较短； 与极化电流位置对称分布相比, 其手征性反转的电流范围变大, 达到暂态构型的时间变短. 

Gyrotropic Motion and Chirality Switching of Magnetic Vortex Driven by Spin Polarized Currents

Three spin polarized currents with the direction of (-1,1-1) were passed through the nanometer disk. The effects of the magnitude and position of the spin polarized currents on the dynamical behavior of magnetic vortex were analyzed by OOMMF  (object oriented micromagnetic framework） software. The results show that the  position of the maximum velocity on the trajectory is relatively fixed when the magnetic vortex core experiences gyrotropic motion. According to this property, we can import defect at the position of the maximum velocity, moving to which the magnetic vortex core can be pinned and  inverted, thus realizing the controllable polarity switching of the magnetic vortex core. The frequency of the gyrotropic motion of the magnetic vortex core can be adjusted by changing the magnitude and position of the spin polarized currents. The chirality switching of the magnetic vortex at the region of high current density, and the inversion time is shorter. Compared with the symmetrical position of polarized currents, the current range of chirality switching is enlarged and the time to the transient state is shortened with the asymmetrical current position.