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Josephson Junction Model of Critical Current in Granular Y1Ba2Cu3O7-δ
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In this paper, the transport critical-current density in a granular superconductor in magnetic fields below about 5 x 10/sup -3/T was calculated, and it was shown that Josephson junctions are limiting transport critical current in these samples and that they lie at the grain boundaries.Abstract:
We calculate the transport critical-current density in a granular superconductor in magnetic fields below about 5 x 10/sup -3/ T. The field dependence in this region is assumed to be controlled by intragranular or intergranular Josephson junctions. Various model calculations are fitted to transport critical-current data on bulk Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7/..sqrt../sub delta/ ceramic superconductors, whose average grain size somewhat exceeds 10 ..mu..m. The results yield an average junction cross-sectional area (thickness x length) of 4--6 ..mu..m/sup 2/. If the junctions are at the grain boundaries, a London penetration depth of about 150--300 nm is inferred, consistent with other estimates. We conclude that Josephson junctions are limiting the transport critical current in these samples and that they lie at the grain boundaries. The parameters of the fit are not consistent with Josephson junctions at twinning boundaries.read more
Citations
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The Flux-Line Lattice in Superconductors
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Magneto-optical studies of current distributions in high-Tc superconductors
TL;DR: In this paper, a review of the magneto-optical imaging technique and experiments on thin films, single crystals, polycrystalline bulk ceramics, tapes and melt-textured HTS materials is presented.
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Relation of critical current irreversibility to trapped flux and microstructure in polycrystalline YBa2Cu3O7
J.E. Evetts,Bartek A. Glowacki +1 more
TL;DR: In this paper, a study of the critical current in YBa2Cu3O7 wires has been made and it has been shown that below 10−3 V m−1 these materials display clear power law behaviour of the form E = kln with n values up to about 16.
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AC susceptibility of high temperature superconductors in a critical state model
TL;DR: In this paper, a critical state model for a granular superconductor is employed to calculate the temperature and AC and DC magnetic field dependence of the complex susceptibility, χ = χ ′ + iχ ″, of a sintered bulk YBa 2 Cu 3 O 7- δ superconductuctor.
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Airy Pattern, Weak-Link Modeling of Critical Currents in High-Tc Superconductors
TL;DR: In this article, the authors measured the transport critical current density at very low magnetic fields in samples of superconducting bulk sintered Y 1 Ba 2 Cu 3 O x, Y 1Ba 2 Cu 4 O x obtained from several sources.
References
More filters
Journal ArticleDOI
The Flux-Line Lattice in Superconductors
TL;DR: In this article, the authors describe the properties of the triangular flux-line lattice (FLL), which is more or less perturbed by material inhomogeneities that pin the flux lines and also by thermal fluctuations.
Journal ArticleDOI
Magneto-optical studies of current distributions in high-Tc superconductors
TL;DR: In this paper, a review of the magneto-optical imaging technique and experiments on thin films, single crystals, polycrystalline bulk ceramics, tapes and melt-textured HTS materials is presented.
Journal ArticleDOI
Relation of critical current irreversibility to trapped flux and microstructure in polycrystalline YBa2Cu3O7
J.E. Evetts,Bartek A. Glowacki +1 more
TL;DR: In this paper, a study of the critical current in YBa2Cu3O7 wires has been made and it has been shown that below 10−3 V m−1 these materials display clear power law behaviour of the form E = kln with n values up to about 16.
Journal ArticleDOI
AC susceptibility of high temperature superconductors in a critical state model
TL;DR: In this paper, a critical state model for a granular superconductor is employed to calculate the temperature and AC and DC magnetic field dependence of the complex susceptibility, χ = χ ′ + iχ ″, of a sintered bulk YBa 2 Cu 3 O 7- δ superconductuctor.
Journal ArticleDOI
Airy Pattern, Weak-Link Modeling of Critical Currents in High-Tc Superconductors
TL;DR: In this article, the authors measured the transport critical current density at very low magnetic fields in samples of superconducting bulk sintered Y 1 Ba 2 Cu 3 O x, Y 1Ba 2 Cu 4 O x obtained from several sources.