Current-induced generation and long-distance motion of skyrmions in synthetic antiferromagnetic materials

Magnetic skyrmions, topologically protected spin textures, exhibit unique quasiparticle characteristics, making them promising candidates for next-generation spintronic devices. Specifically, synthetic antiferromagnetic (SAF) skyrmions, stabilized via interlayer exchange coupling in multilayer systems, achieve ultra-high motion speeds while eliminating the detrimental skyrmion Hall effect through topological charge compensation. Despite significant advancements in generating and manipulating SAF skyrmions, the controlled creation of individual skyrmions at predetermined locations and their reliable long-range transport remain challenging. In this study, we explore both the generation and motion dynamics of SAF skyrmions in Ta/[Pt/Co]3/Ru/[Co/Pt]3/Ta multilayer strips by current pulse excitation. By precisely controlling the amplitude and duration of the current pulses, as well as the external magnetic field strength, we generate skyrmions at defect sites and drive their depinning. Our results demonstrate that SAF skyrmions move along the strip with a Hall angle of 0.2°–0.9°. More importantly, under an optimal external magnetic field, SAF skyrmions can travel long distances—up to the full length of the strip. Furthermore, reversing the driving current causes the SAF skyrmion to reverse its motion direction, allowing for controllable, repeated bidirectional movement along the strip. These findings represent a significant step forward in the development of spintronic devices based on the controlled generation and long-range transport of SAF skyrmions.