Bubble to T-I bar coupling in amorphous film small bubble devices

In GdCoMo amorphous film bubble devices the drive field required for device operation has been found to be linearly dependent on the saturation magnetization of the bubble material over the range from 350 to 1200G. The devices studied were 8000 bit storage chips employing electron-beam-fabricated T-bars, Y-bars, and chevrons of 1μm linewidth. The bubble domain diameter and film thickness were approximately 2μm in all devices. The linear increase in drive field with 4πM
s
is found to be related with the energy required to move a bubble from one permalloy pattern to another across a gap. On the other hand, the field required to overcome coercivity in the movement of a bubble without leaving a single permalloy T-bar is found to be independent of variations in 4πM
s
of the bubble material.