The influence of dzyaloshinskii-moriya interaction (DMI) on the nanosecond pulse-driven domain wall dynamics on CoFeB nanostripe

Abstract Understanding and controlling magnetic domain wall (DW) dynamics is critical for advancing spintronic technologies, including racetrack memories and Magnetic Random-Access Memory (MRAM). While previous studies have shown that the Dzyaloshinskii–Moriya interaction (DMI) enhances DW velocity and suppresses Walker breakdown under continuous magnetic fields, the influence of DMI under nanosecond field pulses remains less explored. In this study, we employed micromagnetic simulations to investigate how varying DMI strengths affect DW motion in CoFeB nanostripes with perpendicular magnetic anisotropy, subjected to nanosecond field pulses. Our results show that DMI significantly increases both the DW velocity and the Walker field. Notably, we observed a transition in Walker breakdown behavior from oscillatory motion to Bloch line nucleation and collision when the DMI strength exceeded approximately 0.6 mJ m −2 . This threshold behavior occurred consistently across nanostripe geometries (thicknesses of 1–2 nm and widths of 50–150 nm). Despite enhanced DW velocity, the geometry of the nanostripes had minimal impact on velocity in the flow regime when DMI was present. Furthermore, the inertial motion of the DW following the pulse was shortened at higher DMI values, indicating additional damping contributions from DMI. Bloch line nucleation above the Walker field, which was previously only observed in sufficiently wide nanostripes, can be observed here in 50 nm wide nanostripes. We also proposed a modified analytical model incorporating a proportionality constant to better fit the observed Walker field behavior. These findings highlight the potential of DMI engineering to tailor DW dynamics using pulsed fields, offering new pathways for designing energy-efficient and structurally stable spintronic devices.