Monte Carlo simulation of magnetization reversal via domain-wall motion in Fe sesquilayers on W(110)

Iron sesquilayers are ultrathin films with coverages between one and two atomic monolayers. They consist of an almost defect-free monolayer with compact islands of a second atomic layer on top. This variation of the film thickness results in a strong interaction between domain walls and the island structure. It makes these systems an ideal laboratory to study the dynamics of domain walls driven by weak external fields. We present computer simulations which provide insight into the role of the thermally activated nucleation processes by which a driven domain wall overcomes the obstacles created by the islands.