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An NDRO for Magnetic Memories by Field Reversal

IP.com Disclosure Number: IPCOM000098005D
Original Publication Date: 1961-Nov-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Chu, K: AUTHOR

Abstract

This is an NDRO (non-destructive readout) method of operating magnetic memories. Conventional NDRO methods drive the magnetization vector away from its easy axis for the purpose of driving the magnetization vector against its anisotropy field. The present mode of operation utilizes the anisotropy of the film to provide a much greater output signal than has heretofore been possible.

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An NDRO for Magnetic Memories by Field Reversal

This is an NDRO (non-destructive readout) method of operating magnetic memories. Conventional NDRO methods drive the magnetization vector away from its easy axis for the purpose of driving the magnetization vector against its anisotropy field. The present mode of operation utilizes the anisotropy of the film to provide a much greater output signal than has heretofore been possible.

(A) shows a magnetic thin film bit 13 formed on a base 11. The easy axis of magnetization of film 13 is indicated by the horizontal arrowed lines, and the hard axis of magnetization is perpendicular to the easy axis. A current drive line 15 is positioned at about 30 degrees off the easy axis of the film 13. A positive signal 1(B) is induced in line 15. This causes the magnetization vector to be rotated away from its easy axis to some positive angle indicated by the dotted line A.

The vector remains at this position as long as signal 1 remains. Then, at the instant when the polarity of the signal is reversed, as indicated by 2(B), the vector rotates from line A to line B. During this rotational movement from line A to the easy axis, the applied magnetic field is aided by the anisotropy. Thus, a large torque is provided and, therefore, a large signal output is obtained.

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