CRYSTAL SYMMETRY EFFECTS IN ION-IMPLANTED PROPAGATION PATTERNS FOR MAGNETIC-BUBBLES - ROOF-TOP DESIGNS

Bubble propagation margins for ion-implanted propagation patterns vary with direction in the (111) garnet film due to the effects of cubic magnetic anisotropy. The margins are poor on one side of a [110] oriented contiguous disk loop, and best on the other side, while perpendicular loops have symmetrical intermediate margins. The poor margin side can be avoided by using “roof-top” designs based on the three-fold crystal symmetry, in which two sloping paths replace the inferior path. In the most compact “multigabled roof-top” design, alternate pairs of elements are oriented at ±30° from the inferior direction. The resulting pattern provides a complete major loop with propagation margins equal to those of the intermediate-direction minor loops of an 8-µperiod circuit. Copyright © 1979 by The lnstitutc of Electrical and Electronics Engineers, Inc.