Novel permalloy gapless propagation circuit

A novel, gapless single-Permalloy, propagation circuit for field access bubble memories has been developed which has a period-to-minimum-feature ratio of 5:1 and a similar packing density to that of C or chevron elements. The circuit consists of gapless chevron-like elements with magnetic lock between them to prevent domain oscillation. Instead of gaps, the minimum feature is the smallest width of the structure, which might be about the diameter of a bubble. The results show low minimum drive field requirement of the structure and a typical short-term propagation margin of at least 15% of the bias field under normal operating conditions.