Browse Prior Art Database

Double Level Field Access Bubble Devices

IP.com Disclosure Number: IPCOM000088562D
Original Publication Date: 1977-Jun-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 19K

Publishing Venue

IBM

Related People

Chandra, AK: AUTHOR [+3]

Abstract

This bubble device is derived from the observation that ion-implanted contiguous disk devices (gapless-structure) require much lower in-plane field to propagate bubbles than the conventional T-bar permalloy-pattern devices (with gaps).

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Double Level Field Access Bubble Devices

This bubble device is derived from the observation that ion-implanted contiguous disk devices (gapless-structure) require much lower in-plane field to propagate bubbles than the conventional T-bar permalloy-pattern devices (with gaps).

Therefore, it is proposed that after contiguous-disk devices have been fabricated by ion-implantation, T-bar patterns are fabricated as overlays with suitable permalloy thickness. The successful operation of the structure depends on the following three factors:

(1) At low in-plane (e.g., around 20 Oe) field, only the contiguous disks are activated to propagate bubbles. The permalloy pattern remains inert due to inadequate field.

(2) At high in-plane field (e.g., around 50 Oe), the permalloy pattern is activated. Moreover, the field gradients from the permalloy overpower those from the contiguous disks. Thus the bubbles propagate according to the path defined by the permalloy.

(3) The tracks of bit positions defined by the contiguous disks and the permalloy are properly intersected so that the bubbles can be propagated on one or the other track.

An example of such superimposed structures is shown in the figure. The horizontal wavy structure 2 enables horizontal propagation at low field levels. The direction of propagation is determined by the sense of field rotation. The Y- bar structure 4 enables vertical propagation at high field. Again, the direction of propagation is determined by the sen...