Study of wall coding in a 180° capped double layer LPE film

Bubble wall states have been investigated in double layer garnet films. All seven wall states which exist in ion-implanted garnet films also exist in the double layer films. In the double layer films, two of these states (1/2,2, 1) and (1,2,2) cannot be obtained by translating the bubbles but are sometimes formed during nucleation. The transitionS=0\rightarrow 1cannot occur during bubble translation but can be produced by radial motion of the bubble wall due to a bias field pulse. The collapse field of S=1 bubbles is 1 Oe higher than that of S=0 bubbles. The results of wall state coding in a device using permalloy elements are described.