The role of charged walls in contiguous-disk bubble devices--A review

Bubble manipulation in ion-implanted contiguous-disk devices relies on the behavior of charged domain walls in the implanted layer. Those characteristics of the charged walls which most strongly impact the device performance are considered. The effects of the trigonal crystalline anisotropy, the demagnetizing fields arising from the pattern geometry, and applied fields ate predominant factors influencing the charged wall properties. Based on the analyses, operating field margins are derived and some simple guidelines for optimization of device designs are proposed. Some of the ways in which the asymmetric nature of charged wall behavior can be utilized to transfer bubbles from one track to another are also discussed.