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 transition cannot 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.