The Observation of the Role of Damping and Interfacial DMI on Directional Domain Wall Creep

Abstract

Previous research has shown that an in-plane magnetic field can lead to asymmetric growth of magnetic domains in thin films with interfacial Dzyaloshinskii-Moriya interaction (DMI). Moreover, in some Pt/Co/Ni systems, the growth becomes highly directional and deviates from the longitudinal direction. It has been suggested that this is caused by a non-zero effective magnetic field acting on the domain wall (DW) that drives the DW magnetization away from its static equilibrium configuration during growth. In previous work, a transient steady-state model was applied to thin films with relatively weak interfacial DMI and low damping coefficient that accurately predicted the aforementioned directional growth. In this work, we experimentally tested a range of DMIs by systematically varying the thin-film stacking. Off-axis directional growth was found less pronounced with larger interfacial DMI and Gilbert damping constant experimentally, as imaged via magneto-optical Kerr effect (MOKE) microscopy, which is consistent with the transient model proposed previously. This work contributes to understanding the complexity of asymmetric domain expansion within the creep regime, while also expanding the applicable property range of the transient steady-state model.