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Random Access Bubble Domain Memory

IP.com Disclosure Number: IPCOM000077170D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Doo, V: AUTHOR [+2]

Abstract

A random-access memory using magnetic bubble domains is comprised of a plurality of conductors located adjacent magnetic sheets in which the bubble domains exist. In addition to the conductors, there are permalloy lines which are used for magnetoresistive sensors.

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Random Access Bubble Domain Memory

A random-access memory using magnetic bubble domains is comprised of a plurality of conductors located adjacent magnetic sheets in which the bubble domains exist. In addition to the conductors, there are permalloy lines which are used for magnetoresistive sensors.

A plurality of memory cells A (enclosed in dashed lines), B,..., F are shown in the figure. Each row A, B of memory cells has one X line and groups of four Y lines. The Y lines are designated "0", "1", "R", and "S" to indicate that they are used for the 0 bit, 1 bit, read, and sensing. Permalloy dots 10 are deposited at the "1" and "R" sites in each memory cell.

Magnetic bubble domains BD are shown in various positions adjacent the conductor lines. For instance, in cell A bubble domain BD is located in the 0 site indicating that cell A has a 0 bit. In cell B bubble domain BD is located in the 1 site, while in cell C bubble domain BD is located at the R site.

The memory operates by selective application of current pulses in the various conductors to move bubble domains to various sites within each cell. These operations are the following: Bubble domain loading -- bubble domains are loaded in each memory cell by having the permalloy dots 10 at sites R and 1 trap a bubble domain, as shown in cell C. The other domains are cleared out of the memory by adjusting the bias field H(z). Writing -- a 1 is written by moving the bubble domains to a site 1. To do this, currents are...