Flux pinning and phase transitions in model high-temperature superconductors with columnar defects

Journal Article · Thu Jul 01 04:00:00 EDT 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.1233· OSTI ID:6488998

Lee, K H; Stroud, D ^[1]; Girvin, S M ^[2]

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1. Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States)
2. Department of Physics, Indiana University, Bloomington, Indiana 47405 (United States)

We calculate the degree of flux pinning by defects in model high-temperature superconductors (HTSC's). The HTSC is modeled as a three-dimensional network of resistively shunted Josephson junctions in an external magnetic field, corresponding to a HTSC in the extreme type-II limit. Disorder is introduced either by randomizing the coupling between grains (model-[ital A] disorder) or by removing grains (model-[ital B] disorder). Three types of defects are considered: point disorder, random line disorder, and periodic line disorder; but the emphasis is on random line disorder. Static and dynamic properties of the models are determined by Monte Carlo simulations and by solution of the analogous coupled overdamped Josephson equations in the presence of thermal noise. Random line defects considerably raise the superconducting transition temperature [ital T][sub [ital c]]([ital B]), and increase the apparent critical current density [ital J][sub [ital c]]([ital B],[ital T]), in comparison to the defect-free crystal. They are more effective in these respects than a comparable volume density of point defects, in agreement with the experiments of Civale [ital et] [ital al]. Periodic line defects commensurate with the flux lattice are found to raise [ital T][sub [ital c]]([ital B]) even more than do random line defects. Random line defects are most effective when their density approximately equals the flux density. Near [ital T][sub [ital c]]([ital B]), our static and dynamic results appear consistent with the anisotropic Bose-glass-scaling hypotheses of Nelson and Vinokur, but with possibly different critical indices.

• DOE Contract Number: FG02-90ER45427
• OSTI ID: 6488998
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 48:2; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
ALKALINE EARTH METAL COMPOUNDS
ANISOTROPY
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRITICAL CURRENT
CRITICAL FIELD
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CURRENTS
DATA
DISLOCATION PINNING
ELECTRIC CURRENTS
EXPERIMENTAL DATA
GRAIN BOUNDARIES
HIGH-TC SUPERCONDUCTORS
INFORMATION
JOSEPHSON JUNCTIONS
JUNCTIONS
LINE DEFECTS
MAGNETIC FIELDS
MAGNETIC FLUX
MICROSTRUCTURE
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
POINT DEFECTS
SUPERCONDUCTING JUNCTIONS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
TYPE-II SUPERCONDUCTORS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES