EP0364101A2
Expired / Lapsed
EP
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Method of forming weak-link Josephson junction, and superconducting device employing the junction
Assignee: Hitachi Ltd
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Filing: 1989-09-12
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Granted: —
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Expires: 2009-09-12
Abstract
Abstract To form a weak-link Josephson junction of the type employing a thin film of an oxide superconductor, a crystal grain boundary produced reflecting an artificial crystal defect is utilized as the weak-link junction. The crystal grain boundary (45) is formed by a method in which atoms of different species are deposited on a predetermined part (42) of the surface of a substrate (40) the predetermined part of the surface of a substrate (40) is disturbed, or parts of different crystal face orientations are formed at the surface of a substrate (40). Then a superconducting thin film (44) is epitaxially grown on the substrate (43). Alternatively the predetermined part of the superconducting thin film (44) epitaxially grown on a substrate (43) is diffused with atoms of different species hampering a superconducting or the predetermined part of the superconductivity thin film (44) is disturbed, the superconducting thin film (44) is then annealed, Also. a superconducting device employing the weak-link junction is disclosed.
Inventors
- 👤 Kazumasa Takagi
- 👤 Yuuichi Madokoro
- 👤 Tokuumi Fukazawa
- 👤 Katsuki Miyauchi
- 👤 Yoshimi Kawanami
- 👤 Toshiyuki Aida
- 👤 Yukio Honda
- 👤 Masaaki Futamoto
- 👤 Masahiko Hiratani
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 21:34
CPC Classifications
H; H10; H10N; H10N60/00; H10N60/01; H10N60/0912; H10N60/0941; Y; Y10; Y10S; Y10S505/00; Y10S505/70; Y10S505/701; Y10S505/702; Y10S505/725; Y10S505/729
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
99 words
A method of forming a weak-link Josephson junction comprising the step of irradiating a substrate with a substance, thereby to process said substrate so as either to deposit said substance in the form of a line on a surface of said substrate or to damage the surface of said substrate in the form of a line by virtue of said substance, and the step of epitaxially growing a thin film of an oxide superconductor on the processed substrate, thereby to form a crystal grain boundary on said line, said crystal grain boundary being used as a weak-link Josephson junction.
Claim 2
Independent Claim
99 words
A method of forming a weak-link Josephson junction comprising the step of irradiating a substrate with a substance, thereby to process said substrate so as either to deposit said substance in the form of a line on a surface of said substrate or to damage the surface of said substrate in the form of a line by virtue of said substance, and the step of epitaxially growing a thin film of an oxide superconductor on the processed substrate, thereby to form a crystal grain boundary on said line, said crystal grain boundary being used as a weak-link Josephson junction.
Claim 3
Dependent Claim
26 words
A method of forming a weak-link Josephson junction as defined in Claim 1, wherein the processing of said substrate is performed by a focused ion beam.
Claim 4
Dependent Claim
33 words
A method of forming a weak-link Josephson junction as defined in Claim 2, wherein said focused ion beam affords a dose within a range of 5 x 10¹¹ - 5 x 10¹⁸ /cm².
Claim 5
Independent Claim
106 words
A method of forming a weak-link Josephson junction comprising the step of irradiating a thin film of an oxide superconductor epitaxially grown on a substrate with a substance for lowering a critical current density, thereby to process said thin film so as either to diffuse said substance in the form of a line within the thin oxide-superconductor film or to damage the oxide-superconductor thin film in the form of a line by virtue of said substance, and the step of annealing the processed oxide-superconductor film, thereby to form a crystal grain boundary on said line, said crystal grain boundary being utilized as a weak-link Josephson junction.
Claim 6
Independent Claim
106 words
A method of forming a weak-link Josephson junction comprising the step of irradiating a thin film of an oxide superconductor epitaxially grown on a substrate with a substance for lowering a critical current density, thereby to process said thin film so as either to diffuse said substance in the form of a line within the thin oxide-superconductor film or to damage the oxide-superconductor thin film in the form of a line by virtue of said substance, and the step of annealing the processed oxide-superconductor film, thereby to form a crystal grain boundary on said line, said crystal grain boundary being utilized as a weak-link Josephson junction.
Claim 7
Dependent Claim
26 words
A method of forming a weak-link Josephson junction as defined in Claim 4, wherein the irradiation with said substance is performed by a focused ion beam.
Claim 8
Dependent Claim
33 words
a method of forming a weak-link Josephson junction as defined in Claim 5, wherein said focused ion beam affords a dose within a range of 5 x 10¹¹ - 5 x 10¹⁸ /cm².
Claim 9
Independent Claim
55 words
A method of forming a weak-link Josephson junction comprising the step of epitaxially growing a thin film of an oxide superconductor on a substrate on which sections different in crystal face orientation are provided, thereby to form a crystal grain boundary between said sections, said crystal grain boundary being used as said weak-link Josephson junction.
Claim 10
Independent Claim
55 words
A method of forming a weak-link Josephson junction comprising the step of epitaxially growing a thin film of an oxide superconductor on a substrate on which sections different in crystal face orientation are provided, thereby to form a crystal grain boundary between said sections, said crystal grain boundary being used as said weak-link Josephson junction.
Claim 11
Dependent Claim
20 words
A superconducting device comprising a weak-link Josephson junction formed by a method as defined in Claim 1, 4 or 7.
Claim 12
Dependent Claim
19 words
A superconducting device as defined in Claim 4, said superconducting device being a thin-film SQUID (superconducting quantum interference device).
References Cited (Backward Citations)
No citation records indexed.
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