Effect of Dipolar Interactions for Domain-Wall Dynamics in Magnetic Thin Films

We study the effect of long-range dipolar forces on the dynamics and morphology of domain walls in magnetic thin films by numerical simulations of the spin-1 random-field Ising model. By studying the size distribution of avalanches of domain-wall motion arising as a response to quasistatic external driving, we observe a crossover from the case dominated by short-range interactions to another universality class where the long-range dipolar forces become important. This crossover is accompanied with a change of the domain-wall morphology from a rough wall to walls with a zigzag structure.