George Keefe

US Patent:

42636620, Apr 21, 1981

Filed:

Dec 28, 1979

Appl. No.:

6/107993

Inventors:

George E. Keefe - Montrose NY
Emerson W. Pugh - Mount Kisco NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11C 1908

US Classification:

365 36

Abstract:

Guard rails are described for particular use with magnetic bubble domain chips using contiguous propagation elements. These guard rails generally surround the active device area (storage area) of the chip and are used to move stray bubble domains from the storage area to the edge of the chip, or to a collapser etc. , and also to prevent stray bubbles from entering the active device area. These guard rail structures are comprised of contiguous propagation elements characterized by an undulating edge and a smooth edge, both of which generally move bubble domains away from the active device area in response to the reorientation of the same magnetic drive field. In one embodiment, the guard rail is a spiral structure surrounding the active device area, having one end in the interior of the magnetic bubble chip adjacent to the active device area, and another end near the edge of the chip, or near a bubble annihilator, etc. In another embodiment, the guard rail is comprised of a plurality of structures generally defining a broken-spiral which surround the active device area. One end of each of structure is located near the active device area, while the other end is disposed toward the edge of the magnetic bubble chip.

US Patent:

40074455, Feb 8, 1977

Filed:

Dec 31, 1974

Appl. No.:

5/537800

Inventors:

George E. Keefe - Montrose NY
Yeong S. Lin - Mount Kisco NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11C 1114

US Classification:

340174TF

Abstract:

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.

US Patent:

39887227, Oct 26, 1976

Filed:

Dec 31, 1974

Appl. No.:

5/537804

Inventors:

George E. Keefe - Montrose NY
Mark H. Kryder - Yorktown Heights NY
Yeong S. Lin - Mount Kisco NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11C 1114

US Classification:

340174TF

Abstract:

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.

US Patent:

39965724, Dec 7, 1976

Filed:

May 13, 1975

Appl. No.:

5/576950

Inventors:

George E. Keefe - Montrose NY
Yeong S. Lin - Mount Kisco NY
Laurence L. Rosier - San Jose CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11C 1114

US Classification:

340174TF

Abstract:

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.

US Patent:

44033052, Sep 6, 1983

Filed:

Dec 22, 1980

Appl. No.:

6/218989

Inventors:

George E. Keefe - Montrose NY
Ian L. Sanders - Sunnyvale CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11C 1908

US Classification:

365 16

Abstract:

An improved non-data reversing one-way bubble transfer switch for contiguous disks is disclosed. The switch has a conductor arrangement in which one edge of the conductor is substantially concentric with and overlapping with the major loop which is in the form of a plurality of scallops. The major loop extends in a direction substantially transversely to one of the three primary crystallographic axes in the bubble material so as to have a propagation track with a high margin on one side and a low propagation margin on the other side. The tip of a minor loop end portion is aligned substantially concentric with the scalloped concave portion of the major loop. This switch has a maximum bias field margin and a maximum phase margin.

US Patent:

41640292, Aug 7, 1979

Filed:

Oct 5, 1977

Appl. No.:

5/839720

Inventors:

George E. Keefe - Montrose NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11C 1908

US Classification:

365 36

Abstract:

A magnetic bubble storage system and a method for making it using only two masking steps, one of which is critical. In a preferred embodiment, the storage regions are comprised of ion implanted propagation elements which can be contiguous with one another. The functions of write, read, storage, transfer between storage elements in different shift registers, and annihilation are provided by the method in which the same mask is used to define ion implanted regions and for formation of conductor metallurgy. Permalloy bridges over ion implanted regions are used to provide transfer of information between one storage element and another. In a preferred embodiment, NiFe is used for sensing, annihilation, and transfer of information, while the storage registers are comprised of ion implanted regions defining contiguous propagation elements of generally circular geometry.

US Patent:

56420455, Jun 24, 1997

Filed:

Aug 18, 1995

Appl. No.:

8/516846

Inventors:

George Andrew Keefe - Montrose NY
Roger Hilsen Koch - Amawalk NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G01R 33022
G01R 33025
G01R 3304
G01V 308

US Classification:

324244

Abstract:

An improved magnetic field gradiometer having major and minor correction circuits is disclosed. The major correction circuits cancel the main components of an applied magnetic field, such as the earth's uniform field, and the minor correction circuits correct for smaller, but still significant effects, such as assembly imperfections and unavoidable cross-talk between the elements of the gradiometer. Also disclosed is a method for processing the gradient data from the gradiometer to enable the positions of magnetic objects to be located in space.

US Patent:

41422503, Feb 27, 1979

Filed:

Dec 30, 1976

Appl. No.:

5/755897

Inventors:

George E. Keefe - Montrose NY
Yeong S. Lin - Mt. Kisco NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11C 1908

US Classification:

365 36

Abstract:

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.