We investigate the mechanism of analogue-like switching of PtMn/[Co/Ni] multilayers induced by spin-orbit torques. X-ray photoemission microscopy performed during magnetization reversal driven by current pulses shows that sequential switching of reproducible domain patterns can be achieved. Switching proceeds by domain wall displacement starting from the edges of blocked ferromagnetic domains, which do not switch for either direction of the current and represent up to 24% of the total ferromagnetic area. The antiferromagnetic PtMn layer has a granular texture, with the majority of the domains being smaller than 100 nm, whereas the ferromagnetic domains in [Co/Ni] are typically larger than 200 nm. The blocked domains and the granular distribution of exchange bias constrain the origin as well as the displacement of the domain walls, thus leading to highly reproducible switching patterns as a function of the applied current pulses. These measurements clarify the origin of the memristive behavior in antiferromagnet/ferromagnet structures and provide clues for further optimizing spin-orbit torque switching and memristivity in these systems.

中文翻译：

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Pt-Mn / [Co / Ni]多层膜的多畴忆阻开关

我们研究了自旋轨道转矩引起的PtMn / [Co / Ni]多层类似开关的机制。在电流脉冲驱动的磁化反转过程中执行的X射线光电子显微镜显示，可以实现可重复畴模式的顺序切换。开关通过从受阻铁磁畴的边缘开始的畴壁位移进行，该铁磁畴在电流的任一方向均不开关，并且占总铁磁面积的24％。反铁磁PtMn层具有颗粒状纹理，大多数畴小于100 nm，而[Co / Ni]中的铁磁畴通常大于200 nm。受阻的区域和交换偏斜的颗粒状分布会限制区域壁的起源以及位移，因此，根据所施加的电流脉冲，可产生高度可复制的开关模式。这些测量结果清楚了反铁磁体/铁磁体结构中的忆阻行为的起源，并为进一步优化这些系统中的自旋轨道转矩切换和忆阻性提供了线索。