Browse Prior Art Database

Increasing Reliability in Bubble Domain Systems

IP.com Disclosure Number: IPCOM000083992D
Original Publication Date: 1975-Aug-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Chang, H: AUTHOR

Abstract

Dynamic conversion is an effect which occurs in bubble domain systems and which limits the reliability and data rates in such systems. The result of this effect is that bubble domains, which undergo dynamic conversion, tend to exhibit scatters in both their speed and deflection angle in a gradient magnetic field. As is the case with hard bubbles, this effect is explained by the presence of different numbers of vertical Bloch lines in the bubble domain walls.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 81% of the total text.

Page 1 of 2

Increasing Reliability in Bubble Domain Systems

Dynamic conversion is an effect which occurs in bubble domain systems and which limits the reliability and data rates in such systems. The result of this effect is that bubble domains, which undergo dynamic conversion, tend to exhibit scatters in both their speed and deflection angle in a gradient magnetic field. As is the case with hard bubbles, this effect is explained by the presence of different numbers of vertical Bloch lines in the bubble domain walls.

Hard bubble domains are often suppressed by using a capping wall (such as an ion-implanted layer, an exchange coupled permalloy layer, or double-epitaxial layers), or by using low q materials. However, it has been observed that, even in ion-implanted garnet films where fresh bubble domains had no scatter in speed or direction, bubbles start to exhibit speed and direction scattering after many cycles of operation. This phenomenon appears similar to the phenomenon of creeping which occurs in permalloy thin films. Both phenomena are cumulative and depend on the speed of magnetization reversal.

It is proposed to rejuvenate bubble domain systems by replacing old bubble domains by new ones from time-to-time. This allows the use of increased speeds to provide higher data rates and should increase the reliability of bubble devices.

The circuit shown includes a current-controlled switch, an AND circuit, a bubble domain generator, and a bubble domain annihilator. The AND...