Patent US3582912A successfully refreshed from Google Patents.
US3582912A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thin film magnetic information stores
Assignee: Centre National de la Recherche Scientifique
•
Filing: 1968-03-08
•
Granted: 1971-06-01
•
Expires: 1988-03-08
Abstract
Abstract In a binary data information store, a multibit storage member in the form of a thin film magnetic structure includes at least one layer of ferromagnetic alloy and one layer of antiferromagnetic alloy, both of which are magnetized with identically orientated uniaxial anisotropy axes with hysteresis cycles which are substantially rectangular in the direction of said axes, the two layers are magnetically coupled in such a way that, once an information pattern impressed in the antiferromagnetic alloy layer, a corresponding information pattern is preserved in said ferromagnetic alloy layer irrespective of parasitic fields tending to variations of magnetization conditions, such for instance as any demagnetizing fields, and of temporarily localized variations of magnetization which may occur during readout operations.
Inventors
- 👤 Jean Valin
- 👤 Jean-Claude Bruyere
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:55
CPC Classifications
G; G11; G11C; G11C13/00; G11C13/04; G11C13/06; H; H01; H01F; H01F10/00; G11B; G11B5/00; G11B2005/0002; G11B2005/0005; G11B2005/0021; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/923; Y10S428/924; Y10S428/926; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12771; Y10T428/12861; Y10T428/12889; Y10T428/12896; Y10T428/12931; Y10T428/12944; Y10T428/12951
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
52 words
A thin layer magnetic structure for use as a binary information store comprising: an antiferromagnetic alloy layer; and a ferromagnetic alloy layer of uniaxial anisotropy, said layers being so positioned with respect to each other to effect a tight magnetic exchange interaction of the momentums of their magnetic and relatively aligned spins.
Claim 2
Dependent Claim
52 words
A thin layer magnetic structure for use as a binary information store comprising: an antiferromagnetic alloy layer; and a ferromagnetic alloy layer of uniaxial anisotropy, said layers being so positioned with respect to each other to effect a tight magnetic exchange interaction of the momentums of their magnetic and relatively aligned spins.
Claim 3
Dependent Claim
59 words
A thin layer magnetic structure for use as a binary information store comprising: an antiferromagnetic alloy layer; and a ferromagnetic alloy layer, said layers being in contact with each other and being in tight magnetic exchange interaction coupling only at localized points of their contact area and having zero magnetic coupling outside said localized points in their contact area.
Claim 4
Dependent Claim
59 words
A thin layer magnetic structure for use as a binary information store comprising: an antiferromagnetic alloy layer; and a ferromagnetic alloy layer, said layers being in contact with each other and being in tight magnetic exchange interaction coupling only at localized points of their contact area and having zero magnetic coupling outside said localized points in their contact area.
Claim 5
Dependent Claim
37 words
A thin layer magnetic structure as defined by claim 2 in which said ferromagnetic alloy in that portion having zero magnetic Coupling with said antiferromagnetic alloy is magnetically saturated in the direction of its axis of anisotropy.
Claim 6
Dependent Claim
57 words
A thin layer magnetic structure for use as a binary information store comprising: an antiferromagnetic alloy layer; a ferromagnetic alloy layer of uniaxial anisotropy; and a thin film of nonmagnetic material interposed between and in contact with said layers, said layers exhibiting magnetic exchange interaction of the momentums of their relatively aligned spins through said nonmagnetic material.
Claim 7
Dependent Claim
57 words
A thin layer magnetic structure for use as a binary information store comprising: an antiferromagnetic alloy layer; a ferromagnetic alloy layer of uniaxial anisotropy; and a thin film of nonmagnetic material interposed between and in contact with said layers, said layers exhibiting magnetic exchange interaction of the momentums of their relatively aligned spins through said nonmagnetic material.
Claim 8
Dependent Claim
25 words
A thin layer magnetic structure for use as a binary information store as defined by claim 4 in which said nonmagnetic material is electrically conductive.
Claim 9
Dependent Claim
66 words
A thin layer magnetic structure for use as a binary information store comprising: an antiferromagnetic alloy layer; and a ferromagnetic alloy layer; say layers being so positioned with respect to each other as to effect a tight magnetic exchange interaction of the momentums of their magnetic and relatively aligned spins, said antiferromagnetic alloy layer being a ferromagnetic alloy doped with a metal imparting an antiferromagnetic character.
Claim 10
Dependent Claim
66 words
A thin layer magnetic structure for use as a binary information store comprising: an antiferromagnetic alloy layer; and a ferromagnetic alloy layer; say layers being so positioned with respect to each other as to effect a tight magnetic exchange interaction of the momentums of their magnetic and relatively aligned spins, said antiferromagnetic alloy layer being a ferromagnetic alloy doped with a metal imparting an antiferromagnetic character.
Claim 11
Dependent Claim
22 words
A thin layer magnetic structure as defined by claim 6 in which the ferromagnetic material in both layers is the same alloy.
Claim 12
Dependent Claim
27 words
A thin layer magnetic structure as defined by claim 7 wherein said ferromagnetic alloy comprises an alloy or iron and nickel and said doping metal is manganese.
Claim 13
Dependent Claim
72 words
A thin layer magnetic structure for use as a binary information store comprising: an antiferromagnetic alloy layer; a first ferromagnetic alloy layer; said layers contacting each other and being tightly magnetically coupled throughout their entire area of contact; a thin film of nonmagnetic material overlying said first ferromagnetic alloy layer; and a second ferromagnetic alloy layer overlying said thin film of nonmagnetic material and loosely magnetically coupled to said first ferromagnetic layer.
Claim 14
Dependent Claim
72 words
A thin layer magnetic structure for use as a binary information store comprising: an antiferromagnetic alloy layer; a first ferromagnetic alloy layer; said layers contacting each other and being tightly magnetically coupled throughout their entire area of contact; a thin film of nonmagnetic material overlying said first ferromagnetic alloy layer; and a second ferromagnetic alloy layer overlying said thin film of nonmagnetic material and loosely magnetically coupled to said first ferromagnetic layer.
Claim 15
Dependent Claim
18 words
A thin layer magnetic structure as defined by claim 9 in which said nonmagnetic material is electrically conductive.
Claim 16
Dependent Claim
93 words
A thin layer magnetic structure for use as a binary information store comprising: an antiferromagnetic alloy layer; and a ferromagnetic alloy layer of uniaxial anisotropy; said layers being so arranged with respect to each other that there is magnetic interaction therebetween and wherein said ferromagnetic layer and that portion of said antiferromagnetic layer adjacent thereto include a first set of localized points of a first direction of magnetization and a second set of localized points of a reverse direction of magnetization, both directions being oriented along the anisotropy axis of said ferromagnetic layer.
Claim 17
Dependent Claim
93 words
A thin layer magnetic structure for use as a binary information store comprising: an antiferromagnetic alloy layer; and a ferromagnetic alloy layer of uniaxial anisotropy; said layers being so arranged with respect to each other that there is magnetic interaction therebetween and wherein said ferromagnetic layer and that portion of said antiferromagnetic layer adjacent thereto include a first set of localized points of a first direction of magnetization and a second set of localized points of a reverse direction of magnetization, both directions being oriented along the anisotropy axis of said ferromagnetic layer.
Claim 18
Dependent Claim
51 words
In combination, a binary digit information store of the thin film magnetic type which includes at least one antiferromagnetic alloy layer and one ferromagnetic alloy layer, said layers being tightly mutually magnetically coupled, and a readout means including an optical electronic scanning apparatus arranged to scan the surface of the store.
Claim 19
Dependent Claim
51 words
In combination, a binary digit information store of the thin film magnetic type which includes at least one antiferromagnetic alloy layer and one ferromagnetic alloy layer, said layers being tightly mutually magnetically coupled, and a readout means including an optical electronic scanning apparatus arranged to scan the surface of the store.
Claim 20
Dependent Claim
72 words
In combination with a binary digit information store of the thin magnetic film type including an antiferromagnetic alloy layer, a first ferromagnetic layer mutually tightly magnetically coupled thereto, a nonmagnetic thin film coating a surface of said first ferromagnetic layer and a second ferromagnetic alloy layer coating said thin magnetic film, readout means of the electrical pulse activated type comprising a pair of arrays of conductors arranged to closely overlie said store.
Claim 21
Dependent Claim
72 words
In combination with a binary digit information store of the thin magnetic film type including an antiferromagnetic alloy layer, a first ferromagnetic layer mutually tightly magnetically coupled thereto, a nonmagnetic thin film coating a surface of said first ferromagnetic layer and a second ferromagnetic alloy layer coating said thin magnetic film, readout means of the electrical pulse activated type comprising a pair of arrays of conductors arranged to closely overlie said store.
Claim 22
Dependent Claim
54 words
The combination defined by claim 13 in which one array of conductors is arranged at right angles to the axis of anisotropy of said ferromagnetic layer and in which means are provided for generating a magnetic field perpendicular to the axis of anisotropy and simultaneously applying electrical pulses to the conductors of said array.
Claim 23
Dependent Claim
65 words
In combination with a binary digit thin film magnetic store of the type which includes an antiferromagnetic aLloy layer, a nonmagnetic thin film coated on a surface of said alloy layer and a ferromagnetic alloy layer coated over said thin film, readout means for said store of the electrical pulse activated type comprising a pair of arrays of conductors arranged to closely overlie said store.
Claim 24
Dependent Claim
65 words
In combination with a binary digit thin film magnetic store of the type which includes an antiferromagnetic aLloy layer, a nonmagnetic thin film coated on a surface of said alloy layer and a ferromagnetic alloy layer coated over said thin film, readout means for said store of the electrical pulse activated type comprising a pair of arrays of conductors arranged to closely overlie said store.
Claim 25
Dependent Claim
61 words
In combination with a binary digit store of the thin magnetic film type which includes an antiferromagnetic alloy layer and a ferromagnetic alloy layer tightly magnetically coupled thereto only at a plurality of discrete memory points, a readout means for said store of the electrical pulse activated type comprising a pair of arrays of conductors arranged to closely overlie said store.
Claim 26
Dependent Claim
61 words
In combination with a binary digit store of the thin magnetic film type which includes an antiferromagnetic alloy layer and a ferromagnetic alloy layer tightly magnetically coupled thereto only at a plurality of discrete memory points, a readout means for said store of the electrical pulse activated type comprising a pair of arrays of conductors arranged to closely overlie said store.
Claim 27
Dependent Claim
40 words
The combination defined by claim 16 and including external means for generating a magnetic field, said means being so arranged with respect to said ferromagnetic layer that said layer is saturated along the direction of its axis of uniaxial anisotropy.
Claim 28
Dependent Claim
77 words
In combination with a thin layer magnetic store of the type in which a layer of an antiferromagnetic alloy is in magnetic interaction with a layer of a ferromagnetic alloy of uniaxial anisotropy, means for selectively heating discrete points of said store to the disorder temperature range of said antiferromagnetic alloy and means for thereafter cooling said store in the presence of an orienting permanent magnetic field directed along the axis of anisotropy of said ferromagnetic layer.
Claim 29
Dependent Claim
77 words
In combination with a thin layer magnetic store of the type in which a layer of an antiferromagnetic alloy is in magnetic interaction with a layer of a ferromagnetic alloy of uniaxial anisotropy, means for selectively heating discrete points of said store to the disorder temperature range of said antiferromagnetic alloy and means for thereafter cooling said store in the presence of an orienting permanent magnetic field directed along the axis of anisotropy of said ferromagnetic layer.
Claim 30
Dependent Claim
45 words
The combination defined by claim 18 in which said selective heating means includes a perforated mask of heat arresting material positioned to overlie said store and a source of coherent energy for temporarily illuminating those portions of said store underlying the perforations in said mask.
Claim 31
Dependent Claim
51 words
The combination defined by claim 18 in which said selective heating means includes a source of coherent energy and means for displacing said source over the surface of said store in accordance with a predetermined pattern of indexed positions and means for activating said source at each one of said positions.
Claim 32
Dependent Claim
25 words
The combination defined by claim 18 including means for generating an alternating magnetic field and for temporarily substituting said alternating field for said permanent field.
Claim 33
Independent Claim
87 words
A method of preparing a thin film magnetic structure which includes a layer of antiferromagnetic alloy in magnetic mutual interaction with a layer of ferromagnetic alloy, the steps comprising: depositing such layers by evaporation of their component elements in the presence of an orienting permanent magnetic field at a temperature higher than the disorder temperature range of the antiferromagnetic alloy; and thereafter cooling the resulting structure in the presence of a magnetic field oriented along the direction of the axis of anisotropy of the ferromagnetic alloy layer.
Claim 34
Independent Claim
87 words
A method of preparing a thin film magnetic structure which includes a layer of antiferromagnetic alloy in magnetic mutual interaction with a layer of ferromagnetic alloy, the steps comprising: depositing such layers by evaporation of their component elements in the presence of an orienting permanent magnetic field at a temperature higher than the disorder temperature range of the antiferromagnetic alloy; and thereafter cooling the resulting structure in the presence of a magnetic field oriented along the direction of the axis of anisotropy of the ferromagnetic alloy layer.
Claim 35
Dependent Claim
50 words
A method as defined by claim 22 which includes the further steps of: selective heating of a predetermined pattern of points in the magnetic structure; and then cooling such points while applying an orienting magnetic field of reverse orientation with respect to the field applied in the first cooling step.
Claim 36
Dependent Claim
38 words
A method as defined by claim 22 which includes the step of depositing a thin nonmagnetic film over the surface of the first deposited layer so that said ferromagnetic and antiferromagnetic layers are separated by a nonmagnetic layer.
Claim 37
Dependent Claim
22 words
A method as defined by claim 22 in which said layers are deposited on a surface of a heat resistant dielectric substrate.
Claim 38
Independent Claim
134 words
A method of preparing a thin film magnetic structure for use as a binary information store, which structure includes an antiferromagnetic alloy layer in mutual magnetic interaction with a ferromagnetic alloy layer, the steps comprising: heating the magnetic structure to a temperature higher than the disorder temperature range of the antiferromagnetic alloy layer; applying an alternating magnetic field oriented in the direction of anisotropy of the ferromagnetic alloy layer; cooling The structure in the presence of said alternating magnetic field; selectively heating discrete points of the cooled structure to the disorder range of temperature of said antiferromagnetic alloy layer; applying a permanent magnetic field saturating the ferromagnetic alloy layer of the structure in one direction of its axis of anisotropy; and cooling said heated discrete points in the presence of said permanent magnetic field.
Claim 39
Independent Claim
134 words
A method of preparing a thin film magnetic structure for use as a binary information store, which structure includes an antiferromagnetic alloy layer in mutual magnetic interaction with a ferromagnetic alloy layer, the steps comprising: heating the magnetic structure to a temperature higher than the disorder temperature range of the antiferromagnetic alloy layer; applying an alternating magnetic field oriented in the direction of anisotropy of the ferromagnetic alloy layer; cooling The structure in the presence of said alternating magnetic field; selectively heating discrete points of the cooled structure to the disorder range of temperature of said antiferromagnetic alloy layer; applying a permanent magnetic field saturating the ferromagnetic alloy layer of the structure in one direction of its axis of anisotropy; and cooling said heated discrete points in the presence of said permanent magnetic field.
Claim 40
Independent Claim
71 words
A method of making a thin film magnetic structure, the steps comprising: depositing on a layer of metal a layer of ferromagnetic alloy, said metal being such that when alloyed with said ferromagnetic alloy an antiferromagnetic material results; and baking said layers at a temperature higher than the disorder temperature of said antiferromagnetic alloy to cause thermal diffusion of said metal into a part of the thickness of said ferromagnetic alloy.
Claim 41
Independent Claim
71 words
A method of making a thin film magnetic structure, the steps comprising: depositing on a layer of metal a layer of ferromagnetic alloy, said metal being such that when alloyed with said ferromagnetic alloy an antiferromagnetic material results; and baking said layers at a temperature higher than the disorder temperature of said antiferromagnetic alloy to cause thermal diffusion of said metal into a part of the thickness of said ferromagnetic alloy.
Claim 42
Dependent Claim
24 words
A method as defined by claim 27 in which said metal is manganese and said ferromagnetic alloy is an alloy of iron and nickel.
Claim 43
Dependent Claim
51 words
The method defined by claim 27 in which said baking step is continued for a period sufficient to cause thermal diffusion of said metal into the complete thickness of said ferromagnetic alloy and including the additional step of depositing on the resulting antiferromagnetic layer, an additional layer of a ferromagnetic alloy.
Claim 44
Dependent Claim
67 words
The method defined by claim 27 in which said baking step is continued for a period sufficient to cause thermal diffusion of said metal into the complete thickness of said ferromagnetic alloy and including the steps of depositing a thin nonmagnetic layer on the surface of the resulting antiferromagnetic alloy and thereafter depositing on the surface of said nonmagnetic layer a further layer of a ferromagnetic alloy.
References Cited (Backward Citations)
US2988466A
Cited
US3139608A
Cited
US3110613A
Cited
US3141920A
Cited
US3423740A
Cited
US3375091A
Cited
US3399129A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |