Simulation of flexible magnetic bubbles in device environments

Abstract

A numerical model for the simulation of the dynamics and deformations of thin film magnetic domains in magnetic bubble devices is described. The motions of the domain wall are calculated from the total effective magnetic field acting on them; the total field includes the equivalent field of the wall energy, the demagnetizing fields, the bias field, and the nonuniform fields from conductors or other sources. The numerical scheme of time integration of the wall motion is described; the simulation time step is adaptively optimized in the presence of incipient numerical instabilities, which are monitored by means of Fourier transformations. The model was used to investigate collapse and run-out of free bubbles and stripe-out and replication of domains under permalloy and current-carrying conductors. The results presented show agreement with experimental data.