Nondestructive sensing of wall-state transition and a dynamic bubble collapse experiment

The dynamic bubble collapse method was used to detect the oscillatory wall motion displacement versus pulsewidth or pulse field strength in low damping as-grown garnet film. It had been speculated that the nondestructive sensing of the bubble state after bias pulsing would provide important information about bubble dynamics. The method of nondestructive sensing for the χ bubble state is based on the principle of "in-plane automotion," and for the σ bubble states, on "automotion II." Because four kinds of bubbles having the same revolution number S = 1 move in different directions for a single combination of in-plane dc field and orthogonal in-plane pulse field having a fast rise-time and slow fall-time pulse shape, the strip line and the optical microscope TV system enable the observer to distinguish among four kinds of bubble states. The transition probability versus the bias pulse field experiment shows that the first transition is clearly demonstrated for the fast fall-time bias pulse, and that the transition process (
\chi+ \rightarrow \chi- \rightarrow \chi+ \rightarrow \chi-
) occurs in sequence for increasing bias pulse field and for increasing bias pulsewidth in the case of slow fall-time.