Magnetic bubble collapse in the presence of a microwave field

Abstract

A bubble collapse experiment has been done on a garnet sample with the composition y 1.92 Sffio.1 Ca O . 98 Fe 4 . 02 GeO.98 0 12 both with and without an applied local microwave field. To explain the experimental results, the analysis of bubble domain waH motion by Callen and Josephs has been modified by introducing a nonlinear velocity-drive characteristic. In the case of no microwave excitation, a good fit between the theory and the experimental data is then obtained. A bubble collapse model in the presence of a microwave field which includes contributions from microwave-produced "dipolar pressure" and "intrinsic pressure" has been made. While some discrepancies exist between theory and experiment, nevertheless these results may be helpful in understanding the observations of microwave bubble generation reported by a number of research groups.