Investigation of Notch Dept Effect on Domain Wall Depinning in Ferromagnetic Nanowires by Micromagnetic Simulation

Abstract

Utilization of topological nanostructure such as magnetic domain wall (DW) as a future generation of non-volatile memory as racetrack memory has been attracted more researchers due to potential to achieve higher speed of data read/writing and capacity. However, completed understanding of DW dynamics was still need to be improved by advanced analysis from the theoretical/simulation or experimental methods. In this study, the effect of geometrical notch dept on domain wall depinning in Permalloy (Py) nanowires by micromagnetic simulation method have been investigated. The varied double notch dept from 10 to 90 nm in 200 nm of wire width were used and the transverse type DW was triggered by nanosecond current pulse to observe the critical depinning current (Jd). It is observed that the depinning current was increased as the notch dept increases. However, the magnitude of Jd have a maximum values for all notch length variation. The increasing of notch length has shifted the maximum Jd to the larger notch dept values. This behavior indicated that the optimum notch design was needed to obtain higher speed and lower depinning energy in the development of domain wall based devices.