Operating characteristics of domain walls in perpendicularly magnetized ferrimagnetic cylindrical nano-wires for three-dimensional magnetic memory

Abstract

We observed field- and current-induced domain wall motion (DWM) in a ferrimagnetic cylindrical nano-wire using a micromagnetic simulation. Two types of domain walls, namely the Hedgehog Bloch point (HBP) and transverse domain wall (TDW), can be generated by controlling the initial state of these systems. In the case of the field-induced HBP motion, depinning and Walker breakdown were observed, whereas they did not appear in the field-induced TDW motion. According to the observation of current-induced DWM, we found that the domain wall mobility in ferrimagnetic cylindrical nano-wires is higher than that in conventional ferromagnetic cylindrical nano-wires owing to the small saturation magnetization. The current-induced HBP motion exhibits depinning, unlike the TDW motion, which corresponds to field-driven DWM. These differences are attributed to the symmetry of the magnetization in the domain walls. These results provide notable insight into the design of three-dimensional memory based on current-induced DWM.