Domain configurations and reversal dynamics in Co-based nanomultilayers

Domain configurations and reversal behaviors in Co-based nanomultilayers have been quantitatively investigated. A sharp transition of domain configuration from a large-area domain pattern to a striped domain configuration with increasing the Co-sublayer thickness has been experimentally observed. The transition was well explained by an analytic theory based on calculating the magnetostatic energy in the multilayered structure by solving Maxwell´s equations in continuum approximation. The transition was found to be ascribed to a competition between the magnetostatic energy and the domain-wall energy. Magnetization reversal dynamics in Co-based nanomultilayers has been investigated by the magnetization viscosity measurement and the real-time domain observation. The reversal behaviors were sensitively changed from wall-motion dominant to nucleation dominant with either increasing the Co-sublayer thickness or increasing the number of repeats. Quantitative analysis revealed that the contrasting reversal behavior was mainly caused by the sensitive change in the wall-motion speed. The reversal ratio of the wall-motion speed to the nucleation rate was found to be an important parameter to characterize the reversal behavior in these systems