Wall states in a bubble moving in a rotating field gradient

In the rotating gradient experiment, a magnetic bubble is in steady-state circular motion. This experiment is reviewed as a method for determining the dynamical wall structure of a magnetic bubble. New data obtained by this technique on a low damping, unimplanted sample are presented. The bubble is brought to a critical velocity where one or two Bloch curves punch through and form vertical Bloch line pairs of opposite twist. A 0.15 Oe, 5.5 MHz ac tickle field was superposed on the dc bias to make possible domain motion. The experimentally determined values of Bloch curve nucleation and punch-through velocities were 2 and 4 m/s, respectively.