Reversible magnetization, critical fields, and vortex structure in grain-aligned YBa[sub 2]Cu[sub 4]O[sub 8]

Journal Article · Wed Mar 01 04:00:00 EST 1995 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.51.6035· OSTI ID:6494595

Sok, J; Xu, M; Chen, W; Suh, B J; Gohng, J; Finnemore, D K; Kramer, M J ^[1]; Schwartzkopf, L A ^[2]; Dabrowski, B ^[3]

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1. Ames Laboratory, U.S. Department of Energy and Department of Physics Astronomy, Iowa State University, Ames, Iowa 50011 (United States)
2. Department of Physics, Mankato State University, Mankato, Minnesota 56002 (United States)
3. Department of Physics, Northern Illinois University, Dekalb, Illinois 60115 (United States)

Reversible-magnetization data have been studied for YBa[sub 2]Cu[sub 4]O[sub 8] in order to determine the thermodynamic properties and the magnetic-field dependence of the superfluid density. By fitting the Hao-Clem variational model to the reversible magnetization data below [ital T][sub [ital c]], superconducting parameters such as the Ginzburg-Landau parameter [kappa], the thermodynamic critical field [ital H][sub [ital c]], and the superconducting order parameter are determined. The upper and lower critical fields [ital H][sub [ital c]2],[ital H][sub [ital c]1], the penetration depth [lambda], and the coherence length [xi] are derived. Within the model there is a direct connection between the magnetization and the superfluid density, so the vortex structure, the behavior of the average order parameter in ([ital H],[ital T]) plane, and the magnetic-field dependence of the superfluid density are obtained. In the high-field region, the evidence of strong vortex fluctuation effects is observed and explained by vortex fluctuation for a three-dimensional superconductor. The mean-field transition temperature [ital T][sub [ital c]]([ital H]) and [ital dH][sub [ital c]2]/[ital dT] near [ital T][sub [ital c]] derived from the analysis of vortex fluctuation effects are comparable with fitting results.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6494595
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 51:9; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COHERENCE LENGTH
COPPER COMPOUNDS
COPPER OXIDES
CRITICAL FIELD
DIMENSIONS
HIGH-TC SUPERCONDUCTORS
LENGTH
MAGNETIC FIELDS
MAGNETIC FLUX
MAGNETIC PROPERTIES
ORDER PARAMETERS
OXIDES
OXYGEN COMPOUNDS
PENETRATION DEPTH
PHYSICAL PROPERTIES
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0065-0273 K
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES