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Nondestructive Readout Memory Device

IP.com Disclosure Number: IPCOM000094344D
Original Publication Date: 1966-Sep-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Jutzi, WW: AUTHOR

Abstract

This magnetic film memory device utilizes eddy-current braking and positive coupling to achieve nondestructive readout. Magnetic storage film 1 is positioned on ground plane 2 in insulated relation. Its easy axis extends in the direction shown. Magnetic keeper 3 is positioned above film 1 in spaced relation. Word line 4 extends beneath keeper 3 above film 1 in parallel relation to the easy axis. Slotted bit line 5 and sense line 6 extend at right angles to the easy axis above a portion of film 1. The remaining portion of film 1 is covered by an eddy-current screen 7 of conductive nonmagnetic material such as copper. Preferably, screen 7 is coplanar with lines 5 and 6.

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Nondestructive Readout Memory Device

This magnetic film memory device utilizes eddy-current braking and positive coupling to achieve nondestructive readout. Magnetic storage film 1 is positioned on ground plane 2 in insulated relation. Its easy axis extends in the direction shown. Magnetic keeper 3 is positioned above film 1 in spaced relation. Word line 4 extends beneath keeper 3 above film 1 in parallel relation to the easy axis. Slotted bit line 5 and sense line 6 extend at right angles to the easy axis above a portion of film 1. The remaining portion of film 1 is covered by an eddy-current screen 7 of conductive nonmagnetic material such as copper. Preferably, screen 7 is coplanar with lines 5 and 6.

Information is written into film 1 in the customary manner by the interaction of orthogonal word and bit fields generated by word line 4 and bit line 5. The writing operation takes into account the switching delay caused by eddy-currents induced in screen 7.

To read stored information nondestructively from film 1, word line 4 is energized by a current pulse. The latter is long enough to rotate the magnetization of the uncovered portion of film 1. The pulse is not long enough to produce any significant rotation of the magnetization in that portion of film 1 which is covered by eddy-current screen 7. When the read pulse terminates, the relatively unrotated magnetization vector in film 1, beneath screen 7, positively restores the rotated magnetization vector in the...