Patent US1329323A successfully refreshed from Google Patents.
Patent EP0344352B1 successfully refreshed from Google Patents.
EP0344352B1
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Method for making artificial layered high-Tc superconductors
Assignee: International Business Machines Corp
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Filing: 1988-06-03
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Granted: 1994-09-28
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Expires: 2008-06-03
Abstract
Abstract This is a method for making layered structures of artificial high-Tc superconductor compounds by which on top of a seed crystal (7) having a lattice structure matching the lattice structure of the superconductor compound to be made, oxide layers (4, 5, 6) of all constituent components are epitaxially grown in a predetermined sequence so as to create a sandwich structure not found in natural crystals. The epitaxial deposition of the constituent components is performed in a reaction chamber having evaporation facilities, inlets for metal-organic gases, and inlets for background gases including oxygen.
Inventors
- 👤 Volker Dr. Graf
- 👤 Carl Alexander Prof.Dr. Müller
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 02:06
CPC Classifications
C; C30; C30B; C30B25/00; C30B25/02; B; B82; B82Y; B82Y30/00; C30B29/00; C30B29/60; C30B29/68; H; H10; H10N; H10N60/00; H10N60/01; H10N60/0268; H10N60/0296; H10N60/0576; H10N60/0604; H10N60/80; H10N60/85; H10N60/855; H10N60/857
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
317 words
Method for making artificial, layered high-T c superconductor compounds by monolayer epitaxy, characterized by the following steps: - placing a monocrystalline substrate (7, 11, 17, 33) of a material from the group comprising strontium titanate SrTiO₃, zirconium dioxide ZrO₂, zinc telluride Zn 1-x Te x , zinc selenide Zn 1-x Se x , BaF₂, cadmium selenide Cd 1-x Se x , and cadmium telluride Cd 1-x Te x , wherein x < 1, in an UHV chamber (27, 28) having a plurality of independent sources (36...40) for materials for epitaxial deposition, - exposing said substrate (7, 11, 17, 33) in a predetermined sequence to as many different ones of said sources (36...40) of constituent materials as the superconductor compounds being made should contain, - activating said sources (36...40) in accordance with a predetermined pattern of activity, said pattern involving · data determining which particular constituent material is to be deposited at any one time; · data relating to the amount and concentration of the particular constituent material to be emitted from the activated source (36...40) · data relating to the period of time the exposure of said substrate (7, 11, 17, 33) to the individual constituent materials should last for one monoatomar/monomolecular layer of the particular constituent material to settle on the current substrate surface; · data relating to the operating temperature at which the exposure is to be performed, said data including information on the operating temperature of the current substrate surface, on the operating temperature of the source (36...40) of the particular constituent material, and on the reaction temperature required for the desired high-T c superconductor material to form in accordance with a particular, desired crystal structure; - repeating the preceding steps as often as corresponds to the number of monomolecular/monoatomar layers the final superconductor compound should contain; - cooling the resulting crystal to ambient temperature and removing it from the UHV chamber (27, 28).
Claim 2
Dependent Claim
26 words
Method in accordance with claim 1, characterized in that the epitaxial deposition of at least part of said constituent materials is made from a gas phase.
Claim 3
Dependent Claim
30 words
Method in accordance with claim 2, characterized in that said gas phase contains the metal atoms to be deposited in the form of an organic compound of the particular metal.
Claim 4
Dependent Claim
28 words
Method in accordance with claim 1, characterized in that the epitaxial deposition of said constituent materials is made from at least one molecular beam of the particular material(s).
Claim 5
Dependent Claim
154 words
Method in accordance with claim 1, characterized in that said monocrystalline substrate (7) consists of octahedral strontium titanate SrTiO₃, that in a first epitaxial operation a first monomolecular layer (6) of lanthanum oxide La₂O₃ is deposited onto said strontium titanate substrate (7), that in a second epitaxial operation a layer (4) of octahedral cuprous oxide Cu₂O is deposited onto said lanthanum oxide monolayer (6), that in a third epitaxial operation a second monolayer (6′) of lanthanum oxide La₂O₃ is deposited onto said cuprous oxide layer (4), that in a fourth epitaxial operation a monolayer (5) of octahedral titanium dioxide TiO₂ is deposited onto said second lanthanum oxide monolayer (6′), the four individual epitaxial operations being performed under controlled conditions regarding time of exposure, concentration of epitaxial source material, and reaction temperature so as to permit the nascent La₂CuTiO₆ crystal to be stoichiometrically correct and to assume a layered, octahedral structure of the ABB′ type.
Claim 6
Dependent Claim
31 words
Method in accordance with claim 5, characterized in that said sequence of four epitaxial deposition operations is repeated as many times as the desired thickness of the resulting superconductor compound requires.
Claim 7
Dependent Claim
161 words
Method in accordance with claim 1, characterized in that said monocrystalline substrate (11) consists of octahedral strontium titanate SrTiO₃, that in a first epitaxial operation a monomolecular layer (12) of lanthanum oxide La₂O₃ is deposited onto said substrate (11), that in a second epitaxial operation a monolayer (8) of mixed aluminium oxide Al₂O 3+ 3 and zirconium oxide Zr⁴⁺O₂ is deposited onto said layer (12) of lanthanum oxide, that in a third epitaxial operation a second layer (9) of lanthanum oxide La₂O₃ is deposited onto said monolayer of mixed oxides, and that in a fourth epitaxial operation octahedral cuprous oxide Cu₂O is deposited onto said second monolayer (9) of lanthanum oxide, the four individual epitaxial operations being performed under controlled conditions regarding time of exposure, concentration of epitaxial source material, and reaction temperature so as to permit the nascent La₂Cu(Al 1/2 , Zr 1/2 )O₆ crystal to be stoichiometrically correct and to assume a layered, octahedral structure of the ABB′ type.
Claim 8
Dependent Claim
221 words
Method in accordance with claim 1, characterized in that said monocrystalline substrate (17) consists of octahedral strontium titanate SrTiO₃, that in a first epitaxial operation a first monomolecular layer (16′) of lanthanum oxide La₂O₃ is deposited onto said monocrystalline substrate (17), that in a second epitaxial operation a first monomolecular layer (13) of octahedral cuprous oxide Cu₂O is deposited onto said lanthanum oxide layer (16′), that in a third epitaxial operation a first monomolecular layer (15) of strontium oxide SrO is deposited onto said monolayer (13) of cuprous oxide, that in a fourth epitaxial operation a first monomolecular layer (14) of tungstic oxide WO₃ is deposited onto said first strontium oxide monolayer (15), that in a fifth epitaxial operation a second monomolecular layer (15′) of strontium oxide SrO is deposited onto said monomolecular layer (14) of tungstic oxide, that in a sixth epitaxial operation a second monomolecular layer (13′) of octahedral cuprous oxide Cu₂O is deposited onto said second strontium oxide layer (15′), and that in a seventh epitaxial operation a second monomolecular layer (16) of lanthanum oxide LaO is deposited onto said cuprous oxide layer(13′), the seven individual epitaxial operations being performed under controlled conditions regarding time of exposure, concentration of epitaxial source material, and reaction temperature so as to permit the nascent Sr₂LaCu₂WO₉ crystal structure of the AA′B type.
Claim 9
Dependent Claim
230 words
Method in accordance with claim 1, characterized in that said monocrystalline substrate (33) consists of octahedral strontium titanate SrTiO₃, that in a first epitaxial operation a first monomolecular layer (23) of yttrium oxide Y₂O₃ is deposited onto said monocrystalline substrate (33), that in a second epitaxial operation a first monomolecular layer (19) of pyramidic cuprous oxide Cu₂O is deposited onto said yttrium oxide layer (23), that in a third epitaxial operation a first monomolecular layer (20) of barium oxide BaO is deposited onto said monolayer (19) of cuprous oxide Cu₂O, that in a fourth epitaxial operation a layer (22) of ribbons of square planar copper oxide CuO₄ polyhedra is deposited onto said barium oxide layer (20), that in a fifth epitaxial operation a second monomolecular layer (20′) of barium oxide BaO is deposited onto said layer (22) of copper oxide polyhedra, that in a sixth epitaxial operation a second monomolecular layer (18) of pyramidic cuprous oxide Cu₂O is deposited onto said second barium oxid layer (20′), and that in a seventh epitaxial operation a second monomolecular layer (23) of yttrium oxide is deposited onto said cuprous oxide layer (18), the seven individual epitaxial operations being performed under controlled conditions regarding time of exposure, concentration of epitaxial source material, and reaction temperature, so as to permit the nascent YBa₂Cu₃O₇ crystal to be stoichiometrically correct and to assume a layered, orthorhombic structure.
Claim 10
Dependent Claim
23 words
Method in accordance with claim 9, characterized in that said first and second monolayers (23) of yttrium oxide have a square planar structure.
Claim 11
Dependent Claim
31 words
Method in accordance with claim 9, characterized in that said YBa₂Cu₃O₇ crystal comprises at least two orthorhombic lattices consisting of Ba₂Cu₃O₅ with an interstacked square planar yttrium oxide Y₂O₃ layer (23).
Claim 12
Dependent Claim
30 words
Method in accordance with claim 9, characterized in that said cycle of seven epitaxial deposition steps is repeated as often as the desired thickness of the resulting layered structure requires.
Claim 13
Dependent Claim
64 words
Method in accordance with claim 9, characterized in that said fourth epitaxial deposition step in which a layer (22) of copper oxide CuO₄ is deposited, is repeated at least once prior to continuing with the fifth step deposition so as to create a layered structure comprising more than one layer (22) of copper oxide CuO₄ between consecutive layers (20, 20′) of barium oxide BaO.
References Cited (Backward Citations)
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