The topological switching of magnetic bubble domain arrays

The process of topological switching of magnetic bubble arrays, in which arrays of bubbles of one direction of magnetisation may be stably and repetitively switched to arrays of the opposite polarity, is described. A qualitative analysis of the various steps in the switching process is discussed, which points to the conclusion that an in-plane dynamic anisotropy must exist in garnet film samples which exhibit stable topological switching. Quantitative analysis is assisted by the observation of the variations in transmitted light intensity when the sample is illuminated by a Helium-Neon laser during switching.