Annihilation of vertical-bloch-line chains in the walls of the second kind of dumbbell domains subjected to joint static bias field and in-plane field

Experiments were statistically carried out on the behavior of vertical-Bloch-line (VBL) chains in the walls of the second kind of dumbbell domains (IIDs) is garnet bubble films subjected to joint action of static bias field H-b and in-plane field H-ip. The curves of the four critical in-plane fields, (H-ip)(IID-ID) (Hip)(IID-OHB) (Hip)(IID-SB) and H-ip' vs H-b were measured and explained. In particular, in terms of two series of IID photos, a new experimental manifestation of the unknown "number effect" of VBL chains was found.