Sperry Corporation

Sperry Rand Corporation

Maynard C Paul

David S Lo

Ernest J Torok

Leslie H Johnson

Gregory J Cosimini

George F Nelson

John A Krawczak

Stanley J Lins

Lawrence G Zierhut

Alan D Kaske

A method of fabricating a thin magnetic film having improved magnetoresistive readout characteristics as a binary memory device is disclosed. The film is initially formed from a metal vapor as a series of discrete grains upon a substrate surface that is heated to approximately 300.degree. C. Upon continued growth of the film, the grains merge at their boundaries forming a continuous thin film, the grain boundary heights of which, e.g., 1000 .ANG., are substantially greater than the thickness, e.g., 320 .ANG., of the eventual thin magnetizable film. The thin film is then rotated while being ion milled at an oblique angle to a substantially uniform film thickness of e.g. 320 .ANG..

Method of improving magnetoresistive effect in thin magnetic film

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 in a magnetizable layer by appropriate drive fields. The magnetizable layer is configured into a data track whose two opposing edges are formed into patterns of asymmetrically shaped edges which form successive narrow portions with wide portions therebetween, and which are formed about the geometric centerline of the data track. The improvement comprises forming a plurality of energy wells along the geometric centerline of the data track and, transverse to the geometric centerline of the data track in the areas of the narrow portions where the cross-ties are stored but not in the areas of the geometric centerline.

Data track for 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:

Cross-tie propagation using offset serration and cross-tie rocking action

Disclosed is a cross-tie wall memory system for the generating, propagating and detecting of binary data represented by the presence or absence of cross-tie, Bloch-line pairs along a cross-tie wall in a thin magnetic data track. The system includes a three-level shift register structure comprised of the following layers: first and second substantially similar, serrated-edged current conductive striplines and a serrated-edged thin magnetic layer data track. The shift register is terminated on one end by a cross-tie, Bloch-line pair generator and on the other end by a cross-tie detector. A data word is stored in the data track between the generator and the detector and is shifted through the detector for readout of the stored data word. The first and second serrated-edged striplines are formed of alternate wide-narrow portions with the wide portion of one stripline oriented above/below the narrow portion of the other stripline. Current signals alternatively coupled to the first and second striplines generate drive fields of differing intensities in the plane of the inductively coupled data track for propagating the cross-tie, Bloch-line pairs therealong.

Generator/shift register/detector for cross-tie wall memory system

Disclosed is a cross-tie wall memory system for the generating, propagating and detecting of binary data represented by the presence or absence of cross-tie, Bloch-line pairs along a cross-tie wall in a thin magnetic layer. The system includes a three-level structure comprised of the following superposed layers: a straight-edged current conductive stripline; a serrated-edged thin magnetic layer data track, and a wide-narrow-edged current conductive stripline terminated on one end by a cross-tie, Bloch-line pair generator. A cross-tie detector is positioned intermediate the ends of the data track and is sandwiched between the data track and the wide-narrow-edged current conductive stripline. An N-bit data word is stored in the data track between the generator and the detector, is shifted through the detector for readout of the stored data word and is then restored into its original stored position by being shifted in a reverse manner along the data track and back through the detector.

Nondestructive readout, random access cross-tie wall memory system

Disclosed is a cross-tie wall memory system for the generating, propagating and detecting of binary data represented by the presence or absence of cross-tie, Bloch-line pairs along a cross-tie wall in a thin magnetic layer. The system includes a three-level structure comprised of the following superposed layers: a straight-edged current conductive stripline; a serrated-edged thin magnetic layer data track, and a wide-narrow-edged current conductive stripline terminated on one end by a cross-tie, Bloch-line pair generator and on the other end by a cross-tie detector.

Symmetrical memory plane for cross-tie wall memory system

A method of and a detector for magneto-resistively reading out the information that is stored in a cross-tie wall memory system. The detector includes two current conductive elements that are positioned along and across the cross-tie wall in a magnetic film that is configured into a data track for sandwiching a plurality of memory cells therebetween. A separate current conductive element is centered over each of the sandwiched memory cells for conducting the read current drive signal out of the data track in the area of the Bloch-line, but forcing the read current drive signal through the data track in the area of the cross-tie. A stored binary 1, represented by a cross-tie, Bloch-line pair, is propagated into one end of the detector and is replicated in all of the sandwiched memory cells; conversely, a stored binary O, represented by the absence of a cross-tie, Bloch-line pair, would be replicated in all of the sandwiched memory cells. The passage of a read current drive signal between the two conductive elements would, by a magneto-resistive readout, indicate the presence, or absence, of the cross-tie, Bloch-line pairs.

Magneto-resistive detector for cross-tie wall memory system

A method of and an apparatus for counting is disclosed. The counter includes a generator of cross-tie, Bloch-line pairs and a shift register of N stages or memory cells along which the cross-tie, Bloch-line pairs are propagated or replicated into a detector. The method includes coupling a series of bipolar push-nucleate replicate signals, each one of which produces a cross-tie, Bloch-line pair in the adjacent downstream memory cell along the shift register. When the shift register is filled, a cross-tie will appear in the detector. This provides an output signal indicating that the N memory cells have been filled by the N replicate signals.

Counter for cross-tie wall memory system

A method of and an apparatus for reading out the information that is stored in a magnetizable layer that is formed of a thin film in which data are stored as inverted Neel wall sections about associated Bloch-lines along a cross-tie wall. The apparatus utilizes a magnetizable layer which is configured into a strip whose two opposing edges are, along its longitudinal axis, formed into mirror-imaged, spaced-apart, repetitive, asymmetrically-shaped patterns which repetitive patterns are formed of successive narrow portions that form wide portions therebetween. The repetitive patterns, when suitable magnetic fields are coupled thereto, form a cross-tie wall along the longitudinal axis of the strip while structuring the cross-ties along the cross-tie wall at the narrow portions and the Bloch-lines along the cross-tie walls and between the adjacent narrow portions. One of the repetitive patterns is configured into a sharp film whose longitudinal axis is transverse the strip's longitudinal axis and whose transverse axis is along the strip's longitudinal axis. The sharp film, in the area extending beyond the strip's two opposing edges, comprises an open flux path film that possesses the characteristic of shape anisotropy providing a magnetic easy axis that is generally oriented along the sharp film's longitudinal axis and along which the sharp film's remanent magnetization resides wherein for all points on the sharp film's edge the angle .beta.' between the sharp film's edge and the sharp film's longitudinal axis is equal to or greater than 0.degree. and less than 45.degree.. Also disclosed is a detector that is associated with the sharp film for reading out the orientation of the sharp film's remanent magnetization along the sharp film's easy axis.

Cross-tail sensor for cross-tie memory

A method of and an apparatus for reading out the informaton that is stored in the magnetizable layer of a cross-tie wall memory system is disclosed. A first embodiment of the apparatus utilizes: a conductive probe, that along its length and is conductively coupled to the magnetizable layer and the tip which is centered at or near the Bloch-line position in the memory segment of the cross-tie wall; a conductive crescent that is oriented concentric to the probe tip and that along its length is conductively coupled to the magnetizable layer; and a readout device that is coupled across the probe and crescent for determining the resistance in the magnetizable layer between the probe tip and crescent as an indicaton of the existence or non-existence of a Bloch-line in the memory segment.

Magneto-resistive readout of a cross-tie wall memory system using a

A data track formed of a strip of magnetic film having substantially zero uniaxial anisotropy, i.e., isotropic, for a cross-tie wall memory system is disclosed. The data-track-defining-strip of isotropic magnetic film utilizes its shape, i.e., its edge contour induced anisotropy, rather than its easy axis magnetic field induced anisotropy, to constrain the cross-tie wall within the planar contour of the film strip. The use of the shape induced anisotropy of an isotropic strip of magnetic film permits the use of nonlinear, i.e., curved, data tracks which curved data tracks were not permitted by the prior art cross-tie wall memory systems that were limited to the use of anisotropic magnetic film.

Isotropic data track for cross-tie wall memory system

The design of a magnetic film strip for defining the data track of a cross-tie wall memory system is disclosed. The design involves the conformation or shaping of the opposing edges of the film strip into repetitive, rounded, asymmetrical serrated edge contours. The serrated edge shape structures the cross-tie of each cross-tie, Bloch-line pair at the narrowest width dimension across the film strip while the Bloch-line is positioned at the widest width dimension across the film strip or at the round, convex, portion of the repetitive serrated edge shape. The asymmetrical, rounded edge contour is substantially in alignment with the natural contour of the magnetization that is oriented around a Bloch-line that is positioned on the cross-tie wall, which cross-tie wall is aligned along and superposed the geometric centerline of the film strip.

Rounded serrated edge film strip geometry for cross-tie wall memory

A method of and an apparatus for reading out the information that is stored in the magnetizable layer of a cross-tie wall memory system is disclosed. The apparatus utilizes: a conductive pillar that is centered over and is conductively coupled to the Bloch-line position in the memory segment of the cross-tie wall in the magnetizable layer; a conductive ring that is oriented concentric to the pillar and that is conductively coupled to the magnetizable layer; and a readout device that is coupled across the pillar and ring for determining the resistance in the magnetizable layer between the pillar and ring as an indication of the existence or not of a Bloch-line in the memory segment.

A method of and a configuration for reading out the information that is stored in a cross-tie wall memory system is disclosed. The apparatus utilizes: a cross-tie, Bloch-line pair transfer system for bit-serially moving a bit-defining-Bloch-line along the cross-tie wall into a memory segment; a noise-cancelling figure-8 sense line that straddles the cross-tie wall; a hard axis drive field H.sub.T that passes, if in existence, a bit-defining-Bloch-line out of the memory segment into one of the loops of the sense line and thus inducing in the sense line loop an output signal that is indicative of the passing, or not, of the Bloch-line into the sense line loop.

Growing community of inventors

Bloomington, MN, United States of America

Maynard C Paul