抄録
This paper proposes two types of dual-conductor bubble circuits: single- and double-combinedsheet bubble circuits. A combined sheet consists of a perforated conductor sheet and a perforated permalloy keeper which have the same aperture patterns. The permalloy keeper is disposed on the upper surface of the conductor. The single-combined-sheet circuit consists of the perforated conductor sheet in level 1 and the combined sheet in level 2. The double-combined-sheet circuit consists of the combined sheets in both levels. The effect of the perforated permalloy keeper and magnetic interactions between the levels, such as a field distortion induced by the keeper in the adjacent level and magnetic shielding of the first-level keeper, are discussed by use of the results measured on scale-up models. The combined sheet produces a stronger drive field because the permalloy keeper enhances a field produced by the conductor. Therefore, the linear current density required for bubble propagation is reduced, which results in a lower power dissipation. The degree of the enhancement increases with the permalloy thickness. The thicker permalloy keeper produces the stronger magnetic interactions between the levels.
