Influence of temperature and in-plane fields on vertical Bloch lines in the walls of the first kind of dumbbell domain

The stability of vertical Bloch lines (VBLs) in the domain walls of the first kind of dumbbell domains (IDs) in garnet bubble films as regards both temperature and in-plane field is investigated experimentally. It is found that there exists a critical in-plane field range [H (1) ip (T), H (2) ip (T)] for the VBLs' annihilation in the walls of IDs at various temperatures from room temperature to T 0 . When H ip ≤ H (1) ip (T), the number of VBLs in the domain walls of IDs is constant; when H (1) ip (T) < H ip < H (2) ip (T), the VBLs in the domain walls of IDs will annihilate gradually and the number of annihilations increases with increasing H ip ; when H ip ≥ H (2) ip (T), the VBLs in the domain walls of IDs annihilate completely. Moreover, the range [H (1) ip (T), H (2) ip (T)] decreases with increasing temperature, while the values of H (1) ip (T) and H (2) ip (T) also decrease, and reach zero at T' 0 and T 0 , respectively.