Evaluation of Scalability for Current-Driven Domain Wall Motion in a Co/Ni Multilayer Strip for Memory Applications

We study current-driven domain-wall (DW) motion and thermal stability of Co/Ni strips with DWs at the step boundaries by detecting DW resistance. The depinning current is around 0.5 mA, while the pinning field is 300 Oe, which corresponds to the thermal stability factor of 54 estimated by self-distribution of the pinning field. The depinning current decreases as the strip width decreases and does not strongly depend on the pinning field. On the other hand, the thermal stability factor increases as the pinning field increases. Therefore, an even lower current with sufficient thermal stability can be achieved by decreasing the strip width and increasing the pinning field.