Wall structure changes in low-loss magnetic bubble materials

Transitions between underdamped and overdamped radial motion in magnetic bubble domains are investigated in a low-loss rare-earth garnet material. Three distinct types of domain wall structures, which are present during underdamped motion, have been identified. Bubble walls were subjected to a bias field pulse (H) and tested for underdamped motion sometime (τ) later. The first type of structure follows the formH = H' exp (τ/τ₀), with 170 nsec< τ₀ <270nsec for the first transition, and is not statically stable. Transitions associated with the second type are characterized by a constant critical angle (Ψ̄c) between the magnetization in the middle of the wall, and the plane of the wall. For the first transition,Ψ̄c = 230, and for the second,Ψ̄c = 370. These structures are statically stable. The third type of structure is not statically stable, andHis independent of τ. The first and second wall structure types are associated with multiple transitions while the third only exhibits a single transition.