Measurements of fluctuation-induced diamagnetism above the superconducting transition in YBa[sub 2]Cu[sub 3]O[sub 7[minus][delta]] single crystals in low magnetic fields: Comparison with paraconductivity

Journal Article · Sun May 01 04:00:00 EDT 1994 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.49.13143· OSTI ID:6662688

Torron, C; Diaz, A; Pomar, A; Veira, J A; Vidal, F ^[1]

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1. Laboratorio de Fisica de Materiales, Departamento de Fisica de la Materia Condensada, Facultad de Fisica, Universidad de Santiago, Santiago de Compostela, 15706 (Spain)

The so-called mean-field-like region will correspond to, approximately, 10[sup [minus]2][approx lt][var epsilon][approx lt]0.15. Beyond the lower [var epsilon] limit, closer to [ital T][sub [ital C][ital O]], both the paraconductivity and [Delta][chi][sub [ital a][ital b]]([var epsilon]) separate from the mean-field region behavior. Although so close to the transition we cannot exclude the influence of small stoichiometric inhomogeneities, these data for [var epsilon][approx lt]10[sup [minus]2] may be explained on the grounds of the three-dimensional [ital XY] model, with a critical exponent of [ital x]=[minus]1/3 for the paraconductivity and [ital x]=[minus]2/3 for the fluctuation-induced diamagnetism. A scenario compatible with the experimental results is characterized by the values of the correlation length amplitude in the [ital ab] plane and in the [ital c] direction of, respectively, [xi][sub [ital a][ital b]](0)=(1.1[plus minus]0.2) nm and [xi][sub [ital c]](0)=(0.12[plus minus]0.02) nm, two Josephson coupled superconducting planes in the unit-cell length, and a complex order parameter with two real components, i.e., conventional [sup 1][ital s][sub 0]-wave pairing or one-complex-component unconventional pairing.

• OSTI ID: 6662688
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 49:18; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

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ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
CRYSTALS
CUPRATES
DIAMAGNETISM
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FLUCTUATIONS
JOSEPHSON EFFECT
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MAGNETISM
MONOCRYSTALS
ORDER PARAMETERS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
VARIATIONS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES