Self-collapse of Dumbbell Domains in Garnet Bubble Films

The self-collapse phenomenon of dumbbell domains was studied experimentally.The coincidence of the bias field region of self-collapse with that of collapse for both the first and second kinds of dumbbells manifests that two necessary conditions for self-collapse are:(1)sufficiently high number of vertical Bloch lines(VBLs)in their walls and(2)these VBLs are in high compression,and there exists the similarity between self-collapse and collapse in mechanism.