Sperry Corporation

Lawrence G Zierhut

David S Lo

Maynard C Paul

Gregory J Cosimini

The memory system incorporates a memory element storing binary digital data in the presence, vel non, of a Y-domain cross-tie. The memory element has a planar contour that is substantially symmetrical about a longitudinal axis and that has edge portions that are nowhere perpendicular or parallel to the longitudinal axis. A stabilizing magnetic field applied perpendicular to the longitudinal axis and in the plane of the memory element forms a first Neel wall along the longitudinal axis and causes the magnetization in the memory element to be formed into first and second domains on opposite sides of the Neel wall. When a writing magnetic field oriented in the plane of the memory element and perpendicular to the longitudinal axis but opposite to the stabilizing magnetic field orientation is coupled to the memory element, there is formed in the memory element a third domain separated from the first and second domains by second and third Neel walls having a join with one end of the first Neel wall. The first, second and third Neel walls form a 'Y'. Because of the nature of this third domain having its magnetization oriented in a direction parallel to the readout current caused to pass through the memory element, it produces a significantly greater difference in the readout signal between the readout of a stored 1 and a stored 0 than that achieved with the prior art cross-tie wall memory element.

Y-domain magnetic memory system

A nondestructive readout, random access memory system is disclosed. The memory is formed of a plurality of discrete thin ferromagnetic film memory elements in which binary data are stored as the presence, or absence, of cross-tie, Bloch-line pairs. Column lines and row lines form a matrix array of the memory elements, one at each column line, row line intersection. Cross-tie, Bloch-line pairs are formed in the memory elements by the selective coincidence of row line and column line write drive fields while readout of the presence, or absence, of the cross-tie, Bloch-line pair is by a coincident row line read drive field and a column read current signal that flows through the memory elements aligned along a selected column. A read amplifier is differentially coupled across the one fully selected memory element to detect a first, or second, opposite polarity output signal that is indicative of the presence, or absence, of a cross-tie, Bloch-line pair at the one fully selected memory element.

Nondestructive readout, random access cross-tie wall memory system

An improved magnetic memory system in which binary data are stored as cross-tie, Bloch-line pairs, which are serially propagated downstream along a cross-tie wall and a magnetizable layer by appropriate drive fields. The magnetizable layer is configured into a data track whose two mirror-image, opposing edges are formed into patterns of asymmetrically shaped edges which form successive narrow portions, or necks, with wide portions therebetween, and which shaped edges are formed about the geometric central line of the data track. The cross-ties are structured in the data track by opposite-edge necks at which the ends of the cross-tie are magnetically stable. The improvement comprises:

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Eagan, MN, United States of America

Lawrence G Zierhut