Bubble propagation by disks formed by ion-implantation

The investigation of implantation conditions for bubble propagation points to the necessity for a minimum dose (
1.5 \times 10^{16}
ions cm
²
) and a sufficiently thick profile (0.4 μ). The use of flat profiles gives uniform implanted layers and allows values of the maximum defect concentration far away from the amorphization threshold. Unlike in permalloy circuits, bubble stability and bias field margins do not increase with the drive field. The propagation is not critically dependent upon disk diameter and spacing.