Low-Field Magnetic Domain Wall Motion and Mobility in CoFeB Nanostripes Influenced by The Dzyaloshinskii-Moriya Interaction

This work examines the effects of the Dzyaloshinskii–Moriya interaction (DMI) on low-field magnetic domain wall (DW) dynamics in perpendicular anisotropy CoFeB nanostripes driven by nanosecond magnetic field pulses. Micromagnetic simulations based on the Landau–Lifshitz equation were performed for DMI strengths from 0 to 1 mJ m⁻² and pulse amplitudes of 0.1 to 1 mT, which are commonly regarded to be within the creep regime. The results show that DMI significantly enhances DW displacement and velocity, with a velocity enhancement of up to approximately eight times higher than in the absence of DMI, primarily due to the emergence of a chiral Néel wall configuration and an effective DMI field that increases DW mobility. However, this enhancement does not scale linearly with DMI strength. Instead, both velocity and displacement exhibit a clear saturation behavior beyond intermediate DMI values (~0.6 mJ m⁻²). Mobility analysis, obtained by fitting simulation results to an analytical DW velocity model, indicates an increase of up to two orders of magnitude with DMI, followed by a similar plateau. These findings highlight a limit to DMI-induced enhancement in the low-field regime, with implications for optimizing DW-based spintronic devices.