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High Speed Bubble Domain Generator

IP.com Disclosure Number: IPCOM000078563D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Hendel, RJ: AUTHOR [+2]

Abstract

The data rate of bubble domain devices is limited either by the domain propagation rate or by the domain generation rate. Recent high-speed measurements have shown that the generation rate obtained from existing bubble generators which utilize a permalloy disk at the entrance of the propagating channel to divide the "mother" domain into two, is considerably slower than the domain propagation rate.

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High Speed Bubble Domain Generator

The data rate of bubble domain devices is limited either by the domain propagation rate or by the domain generation rate. Recent high-speed measurements have shown that the generation rate obtained from existing bubble generators which utilize a permalloy disk at the entrance of the propagating channel to divide the "mother" domain into two, is considerably slower than the domain propagation rate.

Since a new bubble is generated at a rate of one bubble per cycle of an in- plane rotating field, which is also the time required to propagate bubbles toward the adjacent bits, the following two factors are believed to be responsible for the slowness of generation rate: (1) the physical length between adjacent bits is around three times shorter than the circumference of the generator, and thus generations of new bubbles require longer time than propagating domains; and
(2) the response time of the generator to in-plane fields is appreciable, compared to the response time of bubbles to permalloy circuits. It has been found that the latter-factor is particularly severe.

Domain patterns photographed by Bitter technique, indicate that regular closure domains are formed in bubble generators with magnetization parallel to film edges (see Figs. 1A, B & C). "Domain growth" instead of "rotation" is responsible for magnetization reversal. Since the generator is about five times wider than permalloy T-bar I-bar structures, its switching time shou...