Defect-induced regime transitions in domain wall transport in ferromagnetic nanowires

Abstract This study investigates the dynamics of domain walls (DWs) in ferromagnetic nanowires using fast atomistic spin dynamics simulations (FASD), a recently developed computational methodology that enables access to relevant spatiotemporal scales with high efficiency (Murillo-Polo et al 2025 Adv. Theory Simul. 9 e00272). Two types of volumetric structural defects (randomly distributed spheroidal vacancies and internal cylindrical cavities) are analyzed. For vacancy-type defects, an increase in defect concentration or a change in their proximity within a given spatial distribution significantly affects the DW propagation velocity, leading to its reduction. At concentrations exceeding 20%, the dynamics transition from a coherent propagation regime to one dominated by multiple nucleations. On the other side, in systems with cylindrical cavities, DWs propagate faster within the defective region, with velocity showing positive correlation to cavity diameter. Furthermore, increased diameter facilitates spontaneous nucleation of additional DWs. These findings establish design criteria for magnetic memory and logic devices, while demonstrating the utility of the FASD technique for efficient investigation of complex magnetic systems with structural disorder.