自旋波辅助对电流驱动磁畴壁移动的影响及其物理机理

Influence of spin-wave assistance on current-driven magnetic domain wall movement and its physical mechanism

通过微磁学模拟方法研究了长直线磁性纳米带中,自旋波辅助电流驱动磁畴壁移动的相关规律及其物理机制。结果显示,在小电流情形下,自旋波辅助能有效增高电流驱动磁畴壁移动速度,其移动速度随自旋波振幅的增大近似线性增大,随自旋波频率的增高呈现多峰非单调增大;但在大电流情形下,自旋波辅助对电流驱动磁畴壁移动速度的影响较小。进一步研究发现,施加的自旋波不仅驱动磁畴壁移动还能有效增强磁畴壁的垂直磁化强度,其垂直磁化强度的增幅随施加电流的增大而减小;另一方面,电流驱动磁畴壁移动的速度正比于磁畴壁的垂直磁化强度,因此自旋波辅助在小电流情形下能显著增大磁畴壁移动的速度,而大电流情形下,其增幅较小。

The motion of domain walls driven by spin wave assisted current in long linear magnetic nanoribbons and its physical mechanism were investigated by means of micromagnetic simulation.The results show that in the case of small current,the assistance of spin waves can effectively enhance the speed of current-driven magnetic domain wall movement.The increase of its moving speed increases approximately linearly with the increase of the spin wave amplitude,and multimodal non-monotonic increase with the increase of the spin wave frequency;however,in the case of high current,the enhancement of the current-driven magnetic domain wall movement with the assistance of spin waves is small.Further research found that the applied spin wave not only drives the movement of the magnetic domain wall but also effectively enhances the perpendicular magnetization of the magnetic domain wall,and the enhancement of the perpendicular magnetization decreases with the increase of the applied current;on the other hand,domain wall movement by the current-driven is proportional to the vertical magnetization of the magnetic domain wall,so the assistance of spin waves can significantly increase the speed of the magnetic domain wall movement in the case of small currents,while the increase is small in the case of large currents.