A study of bubble stability range in T-bar and chevron circuits

The dependence of the operating bias range for T-bar and chevron propagation patterns upon the thickness of spacing layers, and also upon the thickness and 4 ΠMs of garnet films, is measured and discussed using a simple model neglecting the effects of bubble field. The potential well, which a bubble experiences under the Permalloy elements, is determined by the vertical component of the Permalloy field averaged along the domain wall and does not depend upon 4 ΠMs. The upper and lower thresholds of the bias range for quasistatic propagation are so treated as to be the bias fields which causes the critical diameter of the bubble to stretch across the pattern gaps or along the bars. The model neglecting the effects of the bubble field is believed to be sufficient to explain the experimental data.