Fractal Study of Multi-branched Domains in Garnet Bubble Films

The line-measuring dimension D_line has been developed and selected to describe the curved and branched patterns of multi-branched domains (MBDs) formed by using the“low-bias-field method”in magnetic garnet bubble films. The definition of D_line is given. The domain pattern processing and the “double boundary description” of MBDs are introduced. It has been verified that the MBD patterns truly possess the characteristic of fractal structure over a certain range. The meaningful D_line seems to be a better parameter to quantitatively describe the curved and branched structure of MBDs, and can be related to the nucleation of vertical Bloch lines in their walls.