A model of magnetic bubble propagation patterns using surface charge embedded in a minimum domain configuration

A magnetostatic model of thin film polygon shapes is developed as a design aid for conventional field access magnetic bubble devices. A finite surface element treatment of a general polygon shape represents the magnetization by surface charge residing on domain walls and polygon sides. Domain walls are located according to an algorithm which partitions an arbitrary polygon into a minimum number of domains. The system energy is expressed in terms of magnetic charge density on the surface elements, and minimization of the energy produces the solution for the linear magnetization problem. The accuracy of the two-dimensional analysis is improved by including an approximate treatment of charge distribution on the thin film surfaces. The relatively small number of unknowns permits the analysis of several interacting polygons in device configurations. The normal magnetic field is averaged over the thickness of the bubble material, and contour plots of this field are made for each applied field orientation. The field plots are shown to be useful for initial screening of new device ideas and for predicting performance differences among similar designs.