Spin–orbit torque that originates from spin Hall effect and Dzyaloshinskii–Moriya interaction (DMI) can efficiently move chiral magnetic domain walls in perpendicularly magnetized wires. It has been shown that antiferromagnetically coupled composite domain walls across a ruthenium layer can be driven even faster by exchange coupling torque that is proportional to exchange coupling strength. Here, we report a current-driven motion of composite chiral domain walls in synthetic antiferromagnets with a rhodium spacer layer. It is found that the domain walls in the wire with a rhodium layer do not move as fast as that with a ruthenium layer although the exchange coupling in Co|Rh|Co is stronger than Co|Ru|Co, which is due to the formation of a large DMI at the Rh|Co interface. The Dzyaloshinskii–Moriya interaction at the Co/Rh interface has the same sign and comparable strength to the Pt|Co interface, thus negating the exchange coupling torque. The spin Hall effect from rhodium is found to be as small as ruthenium. Our findings show that rhodium can be used to tailor the DMI strengths in the current-driven motion of chiral domain walls in various magnetic nanostructures.

中文翻译：

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Co/Rh/Co 合成反铁磁体中电流驱动的手性畴壁运动

源自自旋霍尔效应和 Dzyaloshinskii-Moriya 相互作用 (DMI) 的自旋轨道扭矩可以有效地移动垂直磁化线中的手性磁畴壁。已经表明，通过与交换耦合强度成正比的交换耦合扭矩，可以更快地驱动穿过钌层的反铁磁耦合复合畴壁。在这里，我们报告了具有铑间隔层的合成反铁磁体中复合手性畴壁的电流驱动运动。研究发现，尽管 Co|Rh|Co 中的交换耦合强于 Co|Ru|Co，但带有铑层的导线中的畴壁移动速度不如带有钌层的线，这是由于形成Rh|Co 界面处的大型 DMI。Co/Rh 界面处的 Dzyaloshinskii-Moriya 相互作用与 Pt|Co 界面具有相同的符号和相当的强度，从而抵消了交换耦合扭矩。发现铑的自旋霍尔效应与钌一样小。我们的研究结果表明，铑可用于调整各种磁性纳米结构中手性畴壁的电流驱动运动中的 DMI 强度。