US3729726A - Single wall domain arrangement - Google Patents

Single wall domain arrangement Download PDF

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Publication number
US3729726A
US3729726A US00228199A US3729726DA US3729726A US 3729726 A US3729726 A US 3729726A US 00228199 A US00228199 A US 00228199A US 3729726D A US3729726D A US 3729726DA US 3729726 A US3729726 A US 3729726A
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Prior art keywords
elements
domains
arrangement
channel
accordance
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US00228199A
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English (en)
Inventor
A Bobeck
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AT&T Corp
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Bell Telephone Laboratories Inc
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C19/00—Digital stores in which the information is moved stepwise, e.g. shift registers
    • G11C19/02—Digital stores in which the information is moved stepwise, e.g. shift registers using magnetic elements
    • G11C19/08—Digital stores in which the information is moved stepwise, e.g. shift registers using magnetic elements using thin films in plane structure
    • G11C19/0858—Generating, replicating or annihilating magnetic domains (also comprising different types of magnetic domains, e.g. "Hard Bubbles")
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C19/00—Digital stores in which the information is moved stepwise, e.g. shift registers
    • G11C19/02—Digital stores in which the information is moved stepwise, e.g. shift registers using magnetic elements
    • G11C19/08—Digital stores in which the information is moved stepwise, e.g. shift registers using magnetic elements using thin films in plane structure
    • G11C19/0875—Organisation of a plurality of magnetic shift registers

Definitions

  • Copending application Ser. No. 160,841 filed July 8, 1971 for A. H. Bobeck and H. E. D. Scovil describes a fine-grained pattern of magnetically soft elements which not only defines multistage propagation channels for domains but permits lateral displacement of domains from one channel to another as well as certain logic functions.
  • the term fine-grained herein means that adjacent elements of a stage of a channel are spaced apart distances about equal to or less than the diameter ofa domain moved by the pattern.
  • any single wall domain arrangement necessitates certain mechanical operations which result in the introduction of spurious domains into the vicinity of operative domain channels.
  • domains are moved in a layer of epitaxially grown material which is diced into areas sufficiently large to accommodate the channel-defining patterns. The dicing procedure results in abraded edges which give rise to suprious domains during later operation.
  • the pattern of magnetically soft material which defines the domain propagation channels in the field-access arrangement is formed by photolithographic techniques which typically employ alignment patterns which give rise to spurious domains. Both circuit and crystal defects also give rise to spurious domains as is well known. Particularly during the testing of finished domain circuits to establish margin limits are such spurious domains introduced. But even in this situation, the domains have only negligible effect on circuit operation at quasistatic (low frequency) speeds.
  • the problem then is how to prevent the movement of domains from the edge of the domain layer into the vicinity of the operative circuit and, further, how to eliminate spurious domains which are generated in the vicinity of the operative circuit.
  • the problem is compounded by the realization that any implementation which functions in the sense of a familiar guard rail may be operative itself to generate spurious domains and is ineffective in eliminating domains within its confines.
  • the invention is based on the recognition that a single wall domain circuit operative in the field-access mode may be encompassed by a propagation annulus comprising illustratively a fine-grained pattern of magnetically soft elements operative, in response to the already present inplane field, to move spurious domains along radial paths outwardly from the vicinity of the operative circuit.
  • the annulus is effective not only in excluding spurious domains generated, for example, at the edges of the domain layer but also in removing from within its confines any spurious domains which might be created due to alignment patterns or crystal or circuit defects in, for example, the event of a temporary loss of power.
  • a propagation annulus in accordance with one aspect of this invention relieves this pressure allowing domain movement only outwardly through it into a nonoperative portion of a domain layer.
  • a propagation annulus is defined by three concentric circles of elements arranged in .a closed loop chevron pattern with the apices of the elements directed along the loop axis.
  • spurious domains are moved outwardly from an operative circuit encompassed within the closed loop.
  • FIG. 1 is a schematic representation of a single wall domain arrangement including a propagation ring or annulus in accordance with this invention.
  • FIGS. 2 and 3 are schematic representations of portions of the arrangement of FIG. 1.
  • FIG. 1 shows a domain propagation arrangement 10 in accordance with this invention.
  • the arrangement comprises a layer 11 of a magnetic material in which single wall domains can be moved.
  • a pattern of magnetically soft elements is formed by familiar photolithographic techniques for defining domain propagation channels.
  • the illustrative pattern is shown in line diagram form as a major-minor memory organization disclosed in U.S. Pat. No. 3,618,054 of P. I. Bonyhard-U. F. GianolaA. J. Perneski.
  • the major-minor memory organization as well as its implementation and operation is now well known in the art. What is important here is that an operative organization, illustratively implemented in the field-access mode is encompassed by a propagation ring 12 in accordance with this invention for the removal of spurious domains.
  • FIG. 2 shows a portion 13 of ring 12 to include a finegrained pattern of chevron elements. These elements are formed by the same process which forms the channel-defining elements of the major-minor organization when the photographic mask which defines the pattern is suitably adapted.
  • magnetic poles are generated at the inside end of each chevron element; next at the apex of each chevron element; and thereafter at the outside end of each element of the propagation ring.
  • Spurious domains represented by circles D in FIG. 3, are either excluded by the outward progression of poles so generated in the elements of the ring 12 or moved outwardly from the area encompassed by the ring as the number of spurious domains increases.
  • Sources 20 and 22 are under the control of a control "circuit represented by block 23 of FIG. 1 for activation and synchronization.
  • the ring mayzbe used also to clear layer 1 l of domains which arise spuriously during testing and characterization operations prior to high-speed'operation.
  • single wall domains are maintained at a nominal operating size by a bias field supplied by a source represented by block 22 of FIG. 1 as is well known.
  • a decrease in themagnitude of the bias field causes domains to increase in size andfirrally to strip out. If, after testing, the bias field is lowered, all domains in layer 11 strip out and latch onto poles simultaneously generated in the ring 12 by a counterclockwise rotating in-plane field.
  • Two multiple element rings of the type described here may be arranged concentrically, a first to move domains from within, a second to move domains to the areaencompassed within it. lf the second surrounds the first, all spurious domains are moved to a well-defined area between the two rings for annihilation.
  • a double annulus arrangement of this type is particularly suited also in conjunction with operative devices in which the in-plane field is reversed in orientation sequency (viz: from counterclockwise to clockwise) normally during operation.
  • FIG. 1 represents a second annulus of this type as a line designated 30.
  • a propagation annulus with multiple elements as shown in FIG. 2 with apices aligned along a path defined by a closely coiled helix of like elements rather than by closely spaced concentric circles.
  • the helix geometry results in a total clearing of the propagation annulus.
  • the circular geometry permits domains under some conditions to strip out and almost close on themselves into a helical geometry leaving domain tips which may give rise to spurious domains. Particularly at the high speeds contemplated, however, the domain generated by such tips are negligible and the helix is employed to avoid a helical strip domain primarily to approach an ideal condition where the propagation annulus cleans itself of domains constantly.
  • a magnetic arrangement comprising a layer of magnetic material in which single wall domains can be moved and a pattern of elements for defining in said layer a first multistage propagation channel having an axis, said elements having geometries and being disposed to effect a net movement of domains only laterally with respect to said axis in response to a cycle of a magnetic field'reorienting in the plane of said layer.
  • An arrangement in accordance with claim 1 also including a pattern of elements for defining an additional multistage domain propagation channel to said first side of said axis for the movement of domains therein in response to said magnetic field.
  • said elements of said first channel comprise a fine-grained pattern of chevron elements the apices of which align with said axis.
  • An arrangement in accordance with claim 4 also including a third propagation channel defined along a circular axis encompassing said first channel, said third channel including elements of a geometry and so disposed to move domains inwardly across said circular axis in response to said magnetic field.
  • An arrangement in accordance with claim 9 also including means for providing said reorienting magnetic field.
  • An arrangement in accordance with claim 9 also including means for providing a bias field for maintaining domains at a nominal operating size in said layer.

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  • Control Of Motors That Do Not Use Commutators (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)
  • Prostheses (AREA)
  • Hall/Mr Elements (AREA)
  • Earth Drilling (AREA)
US00228199A 1972-02-22 1972-02-22 Single wall domain arrangement Expired - Lifetime US3729726A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US22819972A 1972-02-22 1972-02-22

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US3729726A true US3729726A (en) 1973-04-24

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US (1) US3729726A (ja)
JP (1) JPS511577B2 (ja)
BE (1) BE795535A (ja)
BR (1) BR7301195D0 (ja)
CA (1) CA958807A (ja)
CH (1) CH558067A (ja)
DE (1) DE2307932C3 (ja)
ES (1) ES412081A1 (ja)
FR (1) FR2173039B1 (ja)
GB (1) GB1415203A (ja)
HK (1) HK45577A (ja)
IT (1) IT976280B (ja)
NL (1) NL154349B (ja)
SE (1) SE398407B (ja)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3828330A (en) * 1972-04-07 1974-08-06 Siemens Ag Cylindrical domain progation pattern
US4246645A (en) * 1979-05-21 1981-01-20 Burroughs Corporation Passive annihilator
US4263662A (en) * 1979-12-28 1981-04-21 International Business Machines Corporation Guard rail for contiguous element bubble chips
US4412307A (en) * 1981-09-24 1983-10-25 Bell Telephone Laboratories, Incorporated Magnetic bubble detector

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5427408Y2 (ja) * 1977-06-25 1979-09-06
JPS5549744U (ja) * 1978-09-29 1980-04-01

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3641518A (en) * 1970-09-30 1972-02-08 Bell Telephone Labor Inc Magnetic domain logic arrangement
US3676872A (en) * 1971-06-21 1972-07-11 Bell Canada Northern Electric Propagation of magnetic bubble domains

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3641518A (en) * 1970-09-30 1972-02-08 Bell Telephone Labor Inc Magnetic domain logic arrangement
US3676872A (en) * 1971-06-21 1972-07-11 Bell Canada Northern Electric Propagation of magnetic bubble domains

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
IBM Technical Disclosure Bulletin, Vol. 14, No. 6, Nov. 1971, pg. 1806 1807 *
IBM Technical Disclosure Bulletin, Vol. 15, No. 2, July 1972, pg. 529 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3828330A (en) * 1972-04-07 1974-08-06 Siemens Ag Cylindrical domain progation pattern
US4246645A (en) * 1979-05-21 1981-01-20 Burroughs Corporation Passive annihilator
US4263662A (en) * 1979-12-28 1981-04-21 International Business Machines Corporation Guard rail for contiguous element bubble chips
EP0031890B1 (en) * 1979-12-28 1984-04-04 International Business Machines Corporation Guard rail for contiguous element bubble chips
US4412307A (en) * 1981-09-24 1983-10-25 Bell Telephone Laboratories, Incorporated Magnetic bubble detector

Also Published As

Publication number Publication date
CA958807A (en) 1974-12-03
CH558067A (de) 1975-01-15
JPS4898733A (ja) 1973-12-14
DE2307932B2 (de) 1974-09-12
DE2307932C3 (de) 1975-05-15
DE2307932A1 (de) 1973-08-30
NL7302208A (ja) 1973-08-24
HK45577A (en) 1977-09-16
FR2173039B1 (ja) 1976-05-14
BE795535A (fr) 1973-06-18
IT976280B (it) 1974-08-20
SE398407B (sv) 1977-12-19
NL154349B (nl) 1977-08-15
GB1415203A (en) 1975-11-26
FR2173039A1 (ja) 1973-10-05
ES412081A1 (es) 1976-05-01
JPS511577B2 (ja) 1976-01-19
AU5225973A (en) 1974-08-22
BR7301195D0 (pt) 1974-08-22

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