论文标题
由自旋转移扭矩驱动的铁磁体中域壁的动力学
The dynamics of a domain wall in ferrimagnets driven by spin-transfer torque
论文作者
论文摘要
在易于轴稀土过渡 - 金属金属方面的域壁的自旋转移驱动(Stt驱动的)动力学在理论上和数字上在角度动量补偿点$ T_A $附近进行了研究,并在那里进行了净旋转密度消失。特殊的重点是铁磁性结构域壁和STT的绝热成分的抗磁动力学的异常相互作用,而在抗铁磁铁中不存在,但由于传导电子与过渡金属弹的主要耦合电子的主要耦合,因此在铁磁铁中存在。具体而言,我们首先表明,由于净旋转密度的标志变化,STT诱导的域壁速度在$ t_a $上改变了其标志,从而引起了Ferrimagnets独有的现象,该现象可用于用电气来表征$ t_a $。还表明,STT诱导的域壁进液的频率在$ t_a $处显示出最大值,并且可以在足够高的电流下接近自旋波间隙。最后,我们报告了一个数值观察结果,即随着当前密度的增加,域壁速度开始偏离线性响应结果,呼吁针对由强电流驱动的铁磁体中的域壁动力学提出更全面的理论。
The spin-transfer-torque-driven (STT-driven) dynamics of a domain wall in an easy-axis rare-earth transition-metal ferrimagnet is investigated theoretically and numerically in the vicinity of the angular momentum compensation point $T_A$, where the net spin density vanishes. The particular focus is given on the unusual interaction of the antiferromagnetic dynamics of a ferrimagnetic domain wall and the adiabatic component of STT, which is absent in antiferromagnets but exists in the ferrimagnets due to the dominant coupling of conduction electrons to transition-metal spins. Specifically, we first show that the STT-induced domain-wall velocity changes its sign across $T_A$ due to the sign change of the net spin density, giving rise to a phenomenon unique to ferrimagnets that can be used to characterize $T_A$ electrically. It is also shown that the frequency of the STT-induced domain-wall precession exhibits its maximum at $T_A$ and it can approach the spin-wave gap at sufficiently high currents. Lastly, we report a numerical observation that, as the current density increases, the domain-wall velocity starts to deviate from the linear-response result, calling for a more comprehensive theory for the domain-wall dynamics in ferrimagnets driven by a strong current.