Analysis of permalloy circuits for bubble domain propagation

The magnetostatic field distribution associated with Permalloy circuits for bubble domain propagation is analyzed by the Fourier series method. The analysis is three-dimensional in geometry with two-dimensional variation in magnetization vector. It is found that both the normal component magnetostatic field and its average value are linearly proportional to the in-plane field, unless the magnetization is saturated. The fields decay exponentially from the surface of Permalloy circuits and are highly nonuniformly distributed along the circuits, resulting in nonlinear bubble speed. The calculated results are in good agreement with field measurements obtained from a scale-up model.