International Business Machines Corporation

Yeong S Lin

George E Keefe

George S Almasi

Donald T Tang

Chao N Liu

Mark H Kryder

Burn J Lin

Richard P McGouey

Laurence Lee Rosier

Edward August Giess

Jackson E Stanland

Philip J Grundy

Robert J Hendel

A bubble domain storage system is described which has the best features of contiguous element bubble propagation systems and bubble lattice file systems. An array of magnetic bubble domains, such as a lattice, is moved along contiguous propagation patterns in response to the reorientation of a magnetic field in the plane of the bubble domain film. Adjacent rows of bubble domains in the array move in opposite directions to provide individual storage loops within the array. Information accessing can be achieved by the use of input/output registers similar to those used in other contiguous disk bubble domain storage systems. For example, the storage system can be a conventional major/minor loop organization using contiguous element propagation patterns for the storage registers and for the input/output registers. Every bit position in the storage registers is populated by a bubble domain where the average distance between adjacent bubble domains is less than that in a system where bubbles are isolated from one another. For example, the storage registers can be arranged so that the separation between adjacent bubble domains in the storage registers is 2-3 bubble diameters. The bubbles are coded in terms of the magnetic properties of individual bubble domains, or a double layer structure can be used in which an array of bubble domains is in one layer and information bubble domains are in the other layer, coded in accordance with presence/absence. Viewed another way, the invention is a bubble storage system using contiguous propagation elements which is fully populated by interacting bubble domains.

Contiguous element field access bubble lattice file

A switch for transferring magnetic bubble domains from one propagation path to another using a magnetic charged wall is described. The magnetic charged wall bridges the two propagation paths and causes the domain to strip out along the charged wall. By pulsing an overlying conductor, the charged wall and the associated strip domain will shrink away from one side of the conductor in order to translate the domain to the other side. In contrast with previous transfer gates using current carrying conductors where the magnetic field produced by current through the conductors served as the major bubble translational force, the present switch utilizes a magnetic charged wall as the driving source, the current through the conductor being used only for modification of the charged wall. Therefore, the switching margins are maximized to be substantially the same as the bubble propagation margins and the switching currents required are reduced from those in previously used transfer gates. The present switch is particularly useful as a transfer gate in a major/minor loop memory which is fabricated using ion implanted propagation patterns. Various propagation element geometries can be used to provide the bridging charged wall.

Bubble translation switch using magnetic charged wall

A relational data base system utilizing magnetic bubble domain storage. The bubble domain storage is located on a magnetic chip and includes storage circuitry for storing bubble domains in columns and rows. The bubble domains are coded to represent data, and the rows and columns of bubbles correspond to tables of data which are determined by various relations. Current activated transfer gates located on the magnetic chip are used to select a particular row or a particular column of bubble domains for accessing. The magnetic chip also includes a write circuit for writing bubble domains into storage and a read circuit for reading bubble domains removed from storage. Located off the magnetic chip are column addressing circuits, row addressing circuits, interface circuitry, and a computer central processing unit. The interface circuitry is located between the central processing unit and the bubble domain storage chip, while the column and row addressing circuits provide inputs to a transfer control circuit that is used to activate selected current carrying lines when it is determined to access a particular row or column of bubbles in storage. New information can be entered into any of the stored tables of bubble domains, and information can be removed from any of the stored tables. Also, new tables of information can be provided in storage by combining selected rows or columns of tables already in storage.

Magnetic bubble domain relational data base system

An improved magnetic bubble domain nucleator is provided which uses a magnetic wall, such as a charged wall, Neel wall, or Bloch wall, to assist nucleation. In a preferred embodiment, a magnetic charged wall is produced in an ion implanted region of a magnetic material with an in-plane magnetic field, and an applied nucleating magnetic field is produced by current in a conductor. The combination of the first magnetic field associated with the charged wall and the second magnetic field produced by current through the conductor is sufficient to nucleate a bubble domain in the magnetic medium whereas each of these fields acting alone is not sufficient for nucleation. Since the first magnetic field provides a component of the total nucleating field, the amount of nucleation current required in the conductor is reduced. Any structure that can be used to provide the magnetic charged wall, including ion implanted regions of a magnetic material, or an apertured layer of magnetically soft material is suitable in the practice of this invention. The structure for providing the second magnetic field is conveniently provided by a current carrying conductor, or by a magnetic element having a stray field associated therewith, or even by another magnetic bubble domain. Thus, this invention seeks to use naturally occurring magnetic walls to assist bubble nucleation rather than using additional structure.

Magnetic wall assisted bubble domain nucleator

An improved ion implanted propagation structure for movement of magnetic bubble domains in a storage medium which comprises an additional magnetic layer capable of ion implantation in combination with a bubble domain storage layer in which the bubble domains exist and are moved by the ion implanted layer in response to the reorientation of a magnetic field in the plane of the ion implanted layer. The ion implanted layer (drive layer) can be in intimate contact with the storage layer and exchange coupled thereto, or can be separated from the storage layer by a non-magnetic spacer. The ion implanted layer can comprise different geometry propagation elements and its thickness, 4.pi.M, and other magnetic properties are generally selected to provide flux matching of a charged wall in the ion implanted layer with the flux emanating from the bubble domains to be moved. The charged wall is coupled to the bubble domain by exchange coupling and/or magnetostatic coupling. SU

Ion implanted bubble propagation structure

A lattice file using magnetic bubble domains which are arranged in a regular lattice which is moved or expanded to allow different operations, without requiring the need for bubble domains to be entered into or removed from the lattice. This distinguishes from prior lattice files where new information is entered into the lattice and information to be read is removed from the lattice. In a first embodiment, the inherent stability of the lattice is utilized by providing high density lattice for storage and a relaxed (expanded) lattice for operations such as read and write. Thus, the spacings between the elements in the lattice are changed but their relative positions in the lattice are not changed. In a second embodiment, the lattice is shifted without substantially changing the inter-element spacing and information is written and read from bubble domains magnetostatically coupled to the lattice domains. In both embodiments, the lattice is retained so that elements do not have to be brought into and out of the lattice for the performance of memory and storage functions.

Bubble lattice file using movable fixed lattice

It has been discovered that magnetic bubble domains can be moved in a magnetic medium without requiring shaped structure along which magnetic poles are created for movement of the domains, and without reliance on magnetic fields established by conductor patterns. If a magnetic field is applied in the plane of the magnetic medium, bubble domains will be stretched in a direction parallel or anti-parallel to the field direction depending on the bubble domain polarity. If this magnetic field has an asymmetry in its amplitude versus time waveform, or if an asymmetry is created by a propagation element, bubble domains can be moved in the magnetic material. This discovery can be used to move bubble domains in a magnetic medium without requiring structure having a particular shape for domain movement, and without requiring conductors. Also, improvements can be made to existing propagation structures to make them more useful.

Minimum structure bubble domain propagation

The undulating longitudinal edge of a continuous elongated structure of magnetic material forms a bubble domain propagation path for implementing the continuous movement of magnetic bubble domains under the control of a reorienting in-plane magnetic field. The domains propagate along the periphery of the undulating layer, with the periphery preferably taking the form of linked outwardly convex semi-circles. The structure can be comprised of a magnetically soft material, such as permalloy, or be an implanted region in the magnetic material which supports the bubble domains.

Very high density gapless propagation structure for bubble domains

The data stored in a coincident block access bubble domain memory with bit-organized chips is encrypted by skewing or permuting selected word bits by predetermined amounts. This is implemented by providing an additional current loop on some or all of the chips which overlies the major loop pattern and has nodes at the similar vector poles of the major loop. The proper energization of selected ones of these additional current loops, under the control of a security key, inhibits or suppresses the advance of the bubble domains in the corresponding major loops for a predetermined number of cycles of the in-plane propagating field, thus skewing the word bits in these chips with respect to the remaining word bits in the unsuppressed chips. Decryption is accomplished by further inhibiting the same major loops for the necessary number of cycles to restore word bit synchronization throughout the memory.

Cryptographic magnetic bubble domain memory

A magnetic bubble domain propagation device which is single sided and can be used to move bubble domains in amorphous magnetic films. The propagation structure is comprised of either one or two layers located on a single side of the amorphous magnetic medium. Preferably, the propagation elements in each layer are contiguous to one another to provide maximum density. In a preferred embodiment, the propagation elements are circular, but other geometries can be used. The amorphous magnetic material is deposited over these underlayer propagation elements in order to create a change in the profile of the amorphous material. This change in profile of the amorphous material acts as a restraining barrier to bubble domain movement, so that the bubble domains will move along the proper channel without drifting to other propagation channels, and will move from one propagation element to the next without merely idling at any of the propagation elements.

Single sided, high density bubble domain propagation device

A dynamic pattern display and optical data processing system is provided including magnetic bubble devices which may be operated in real-time to produce a multi-tone (gray scale) two dimensional pattern. The display pattern is obtained by directing a light beam, which in certain applications may be linearly polarized, through a plurality of two-dimensional magnetic bubble arrays combined in a stack arrangement. Each magnetic bubble array constitutes a layer which differs in thickness from the other magnetic bubble layers. Each magnetic bubble array is also electronically driven by its own bubble propagating circuit which produces, in most embodiments, a different 'local transmissivity' which is determined by whether a bubble or an empty space is propagated to the location. The degree of transmitted intensity is an exponential function of the number of magnetic bubble layers, thus n layers provides 2.sup.n steps of transmitted intensity and a four layer structure provides a sixteen tone gray scale display. The electronic portion of the structure may be driven by signals representing mathematical expressions, patterns, manual inputs and the like to generate holograms, holographic complex filters, three-dimensional television pictures, spatial intensity filters, or ordinary two-dimensional multi-tone television pictures.

Dynamic magnetic bubble display system

A method of and apparatus for providing single wall self-biased magnetic domains in a film of uniaxial magnetic material. In addition to the conventional uniaxial magnetic film for supporting the single wall domains, a bias film is located adjacent thereto. The material characteristics of the two films and their thicknesses are chosen such that the exchange coupling between the two films provides the effect of an external field for supporting the single wall domains.

Method of, and apparatus for, establishing self-biased single wall

A method for making a high density magnetic bubble domain system including the functions of read, write, storage, transfer, and annihilation. Only three masking steps are required, of which only one requires critical alignment. The proces makes use of the fact that magnetic disks can be placed on non ion implanted regions without adversely affecting the propagation properties of the implanted regions. Thus, the magnetic disks can be used to define ion implantation masks as well as for providing functions such as generation, propagation, reading, and annihilation. Magnetic elements for generation, storage and propagation, reading and annihilation are deposited in the same non-critical masking step, while all condutors used for writing, reading, and transfer are deposited by a single masking step requiring critical alignment.

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Mount Kisco, NY, United States of America

Yeong S Lin