Stripe-Domain Dynamics in Bu ain Circuits
John A. Copeland · 1973
It is widely known that bubble domains can exist when the bias field is between the elliptic instability (runout) field He and the bubble collapse field Hbc. Values for He and Hbc were calculated by Thiele. It is not widely recognized that long domains can also exist in the bot- tom 20% of this range. Stripes are stable up to the stripe field, Hsc, which is about 0.02 M/po above He for thickness over intrinsic length, hlE, values from 4 to 10. (Hbc is about 0.10 M/po above He.) Values for Hsc were cal- culated by Kooy and Enz of Philips Research Labs. in 1960, although the importance of their result to bubble-domain de- vices was not apparent at the time. The velocity of the domain tip during stripout and contraction such as occurs during domain detection or transfer is important for calculating maxi- mum circuit speeds. This is given by I.' = CG (H - Hsc), where H is the field (bias field plus local field from currents or Perm- alloy elements), G is the wall mobility, and c is a constant approximately equal to 0.5.