Activation Volumes of Wall-Motion and Nucleation Processes

Abstract

The correlation between the activation volumes of wall-motion and nuc1eation processes in Co/Pd multilayers has been investigated. Each activation volume was estimated from the field dependence of the wall-motion speed and the nuc1eation rate, respectively, based on time-resolved domain patterns grabbed by a MOKE microscope system. Both the activation volumes are changed in the same manner around 0.2-1.1 x 10-17 cm3 with changes in the multilayered structure. Interestingly, the correlation between the activation volumes is sensitive to the multilayered structure; the wall-motion activation volume is smaller than the nuc1eation activation volume for a sample having a smaller number of repeats and a thinner Co-Iayer thickness, and vice versa. The correlation is c10sely related with the contrasting reversal modes; the process having the smaller activation volume dominates.