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Memory Elements Using Slotted Magnetic Films

IP.com Disclosure Number: IPCOM000094392D
Original Publication Date: 1966-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 3 page(s) / 53K

Publishing Venue

IBM

Related People

Anacker, W: AUTHOR

Abstract

Memory elements having increased performance capabilities are obtained. Such is realized by utilizing magnetic films in which the anisotropy is defined primarily by slotting the films rather than magnetically inducing the same in them during the film deposition.

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Memory Elements Using Slotted Magnetic Films

Memory elements having increased performance capabilities are obtained. Such is realized by utilizing magnetic films in which the anisotropy is defined primarily by slotting the films rather than magnetically inducing the same in them during the film deposition.

Drawings A and B show one form of slotted magnetic film memory device. A flat sheet of magnetic material such as permalloy is divided by some convenient process, e. g., photoetching, into a plurality of elongated strips or ribbons of magnetic material. Such are very narrow and very closely spaced together. Drawing C shows an alternative form. Narrow strips are etched into the upper and lower sides of a magnetic film which is deposited upon all sides of a bit- sense line conductor.

In both cases the narrow elongated form of each strip gives it a very pronounced shape anisotropy in the direction of the slots, which run parallel with the word lines. Thus, the slotting of the film gives it an easy axis extending parallel with the word lines to a very high degree of accuracy. This alignment is achieved much more closely than in the conventional fabrication process, where an easy axis paralleling the word line direction is induced magnetically in the film during its deposition.

Typical widths of these film strips are 2 mils, with 1/10 mil spacings between strips. The close spacings of the strips make their hard-axis demagnetizing fields more uniformly distributed. The lateral positioning of the strips relative to the word lines is not critical. Several strips can fit beneath one word line conductor of conventional width, as indicated at A and B.

There are two important considerations in the arrangement of orthogonal- mode memory devices. The bit-drive operating margins should be large. The word drive requirements should be low. Bit drive operating margins are inversely related to the ratio alphaH(K)/H(C), where alpha is the a...