公开(公告)号：CA787591A

公开(公告)日：1968-06-11

申请号：CA787591D

Applicant: IBM

Inventor： DAUGHTON JAMES M ,  KEEFE GEORGE E

公开(公告)号：CA1104253A

公开(公告)日：1981-06-30

申请号：CA283189

申请日：1977-07-20

Applicant: IBM

Inventor： ALMASI GEORGE S ,  BOGHOLTZ WILHELM E ,  KEEFE GEORGE E

IPC: G11C11/14 ,  G11C19/08

Abstract: BUBBLE DOMAIN STORAGE USING IMPROVED TRANSFER SWITCH A magnetic bubble domain storage device comprising a plurality of storage shift registers and at least one major shift register, which serves to provide bubble domains to the storage register and to receive bubble domains from the storage registers. A novel transfer switch, or gate, is located between each of the storage registers and the major register? which is typically configured in the conventional major/minor loop type of storage organization. This transfer switch can be made using single level masking or multiple level masking and is characterized in that the locus of bubble domain propagation paths through the switch element generally defines the letter "Y". These propagation paths are from one arm of the Y to the other arm, from one arm of the Y to the stem or base portion, or the reverse where a bubble domain travels from the stem (base) of the Y to one of the arms of the Y. In a particular embodiment, the transfer switch is comprised of a Y-shaped magnetic element having a current carrying conductor which crosses the stem portion of the Y-shaped magnetic element. The particular path travelled by bubble domains through the transfer switch is determined by the presence or absence of a current through the conductor. Thus, the transfer switch is characterized by at least one magnetic element having a current path crossing the stem portion of the element(s). The exact shape, width, length, and thickness of the magnetic element, or elements, of the transfer switch can be chosen by the designer in accordance with the propagation structures that are desired. What is important is that the plurality of paths which the bubbles can follow generally define a Y, where the current path through the transfer switch crosses the path which is along the stem portion of the Y defined by the plurality of propagation paths available.

公开(公告)号：FR2393396A1

公开(公告)日：1978-12-29

申请号：FR7813282

申请日：1978-04-27

Applicant: IBM

Inventor： ALMASI GEORGE S ,  KEEFE GEORGE E ,  LIN YEONG S

IPC: G11C11/14 ,  G11C19/08

Abstract: 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.

公开(公告)号：FR2337400A1

公开(公告)日：1977-07-29

申请号：FR7636410

申请日：1976-11-29

Applicant: IBM

Inventor： KEEFE GEORGE E

IPC: G11C11/14 ,  G11C19/08

公开(公告)号：CA964762A

公开(公告)日：1975-03-18

申请号：CA159094

申请日：1972-12-13

Applicant: IBM

Inventor： ALMASI GEORGE S ,  HENDEL ROBERT J ,  KEEFE GEORGE E

IPC: G11C11/14 ,  G01R33/12 ,  G11C19/08

公开(公告)号：CA960362A

公开(公告)日：1974-12-31

申请号：CA154653

申请日：1972-10-24

Applicant: IBM

Inventor： ALMASI GEORGE S ,  KEEFE GEORGE E

IPC: G11C11/14 ,  G01R33/12 ,  G11C19/08

Abstract: A magnetoresistive sensing device for detection of cylindrical magnetic domains (bubble domains) in magnetic bubble sheets. Cancellation of noise due to fields (such as the propagation (drive) field) which intercept the sensing element is achieved by using two magnetoresistive sensing elements whose combined voltage (or current) output is constant in the absence of a bubble domain. In one sensing element, the measuring current through the element is substantially parallel to the magnetization direction of that element, while in the second element, the measuring current is substantially perpendicular to the magnetization direction of the second element. In a preferred embodiment, two sensing elements are electrically connected in series and the sum of their resistances is constant when the device is being operated, in the absence of domains. When a domain is present, the sum of the resistances is different, so the output of the device changes. Each sensor can be associated with a different information channel (or group of channels) in which domains are propagated.

公开(公告)号：CA943665A

公开(公告)日：1974-03-12

申请号：CA154654

申请日：1972-10-24

Applicant: IBM

Inventor： ALMASI GEORGE S ,  KEEFE GEORGE E ,  LIN YEONG S ,  THOMPSON DAVID A

IPC: G11C11/14 ,  G01R33/09 ,  G11B5/02 ,  G11B5/39

Abstract: 1369573 Magnetic storage devices INTERNATIONAL BUSINESS MACHINES CORP 28 Sept 1972 [26 Oct 1971] 44737/72 Heading H3B A sensor of small magnetic fields, such as bubble domains, comprises a magneto-resistive element whose dimensions are sufficiently small, e.g. 200 angstroms thick, 7À5 microns long and 5 microns wide, as to have both a uniaxial anisotropy field imparted during manufacture, and a shape anisotropy field determined by the relationship of its unequal length and width dimensions, the two anisotropy fields being mutually perpendicular and the larger of the two fields being substantially perpendicular to the magnetic field to be detected. As shown in Fig. 1A, a rectangular magnetoresistive element 18 is associated with an orthoferrite or garnet sheet 10 in which bubble domains are propagated by the combination of a permalloy T and I bar pattern and an in-plane rotating magnetic field H. A rectangular magnetoresistive sensor element 18 formed, e.g. of permalloy; and located on or adjacent to the sheet 10, is connected to a constant current source 20 by leads 19, changes of resistance due to magnetic field proximity being indicated to a utilization means 22 as a change of voltage Vs. The sensor element has an easy axis of magnetization E.A. transverse to its length, and has a shape anisotropy field greater than the uniaxial anisotropy field so that the magnetization vector M is normally directed along the length of the element. When a bubble domain 30, Fig. 1B, is moved into a position adjacent the sensor element 18, the external field H B of the domain coupled with the element causes rotation of its magnetization vector M and consequential change in the element resistance. It is stated that the use of both uniaxial and shape anisotropy enhances the detection sensitivity to small magnetic fields. In a modification. Figs. 2A and 2B, the sensor element is arranged so that it is parallel to an external domain field H B along its length dimension. As before the easy axis of magnetization E.A. extends across the width of the element, but in this case the shape anisotropy field is less than the uniaxial anisotropy field so that the normal position of the magnetization vector M is parallel to the easy direction of magnetization. This vector is rotated towards the length dimension of the element by an adjacent bubble domain 30 as shown in Fig. 2B. The sheet 10 is subjected to a bias field H z derived from a permanent magnet, an energized coil or an adjacent magnetic sheet. The sensor may be used to read out a pattern of domain reversals extending across a moving magnetic tape, Fig. 3A (not shown), in which case the sensor element is mounted with electrical connections on an insulating substrate. Such an element is formed by evaporation deposition on a magnetic sheet or insulating substrate in the presence of a magnetic field with the subsequent selective formation of electrical connections by masking, electroplating and etching.

公开(公告)号：CA831676A

公开(公告)日：1970-01-06

申请号：CA831676D

Applicant: IBM

Inventor： MIDDELHOEK SIMON ,  KEEFE GEORGE E

公开(公告)号：CA1128205A

公开(公告)日：1982-07-20

申请号：CA338281

申请日：1979-10-24

Applicant: IBM

Inventor： CULLUM CLIFTON D JR ,  KEEFE GEORGE E ,  KRYDER MARK H ,  LIN YEONG S

IPC: G11C11/14 ,  G11C19/08

Abstract: MAGNETIC BUBBLE DOMAIN CHIP WITH ENHANCED PROPAGATION MARGINS In magnetic bubble domain chips using layers of crystalline material having in-plane magnetization for propagation, hard bubble suppression, etc., asymmetric propagation often results due to crystalline anisotropies in the layer of in-plane magnetization. In these chips, different propagation margins result for propagation in different directions with respect to the crystalline axes of the in-plane layer. In the present magnetic chip, a plurality of shift registers is provided for movement of bubble domains in a plurality of directions, all of which provide good propagation margins. The registers are aligned in particular directions with respect to the directions of easy stripout of bubble domains in order to avoid the problem of asymmetric propagation. Examples are shown using ion implanted contiguous element propagation patterns organized in a major/minor loop type of storage organization. Y0978-047

公开(公告)号：CA1112362A

公开(公告)日：1981-11-10

申请号：CA288230

申请日：1977-10-06

Applicant: IBM

Inventor： KEEFE GEORGE E ,  LIN YEONG S

IPC: G11C11/14 ,  G11C19/08

Abstract: BUBBLE TRANSLATION SWITCH USING MAGNETIC CHARGED WALL 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 sources, 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.