Study of the in-plane and c-axis fluctuation conductivity of melt-textured YBa2Cu3O7 under hydrostatic pressure

We have experimentally studied the pressure dependence of the fluctuation conductivity in melt-processed YBa 2 Cu 3 O 7 (YBCO) for currents applied parallel or perpendicular to the Cu-O 2 atomic layers. Results show that the asymptotic critical regime is described by the 3D-XY universality class for...

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Bibliographic Details
Published in:The European physical journal. B, Condensed matter physics Condensed matter physics, 2011-10, Vol.83 (4), p.423-428
Main Authors: Mendonça-Ferreira, L., Dias, F. T., Pureur, P., Borges, H. A., Rodrigues, P., Obradors, X.
Format: Article
Language:English
Subjects:
Complex Systems
Condensed Matter Physics
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Exact sciences and technology
Fluid- and Aerodynamics
Granular, melt-textured, amorphous and composite superconductors
Inhomogeneous superconductors and superconducting systems
Physics
Physics and Astronomy
Properties of type I and type II superconductors
Regular Article
Solid State Physics
Superconductivity
Transport properties (electric and thermal conductivity, thermoelectric effects, etc.)
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Summary:We have experimentally studied the pressure dependence of the fluctuation conductivity in melt-processed YBa 2 Cu 3 O 7 (YBCO) for currents applied parallel or perpendicular to the Cu-O 2 atomic layers. Results show that the asymptotic critical regime is described by the 3D-XY universality class for both in-plane and off-plane conductivity components. The dynamical exponent for the in-plane conductivity component is z = 1.5, independently of the applied pressure. However, a pressure induced crossover in the dynamical universality class is observed in the c-axis fluctuation conductivity, where the exponent changes gradually from z = 1.5 to z = 2. The Ginzburg number increases with pressure for both crystalline orientations. This behavior suggests that the in-plane and c-axis components of the G-L coherence length decrease upon pressure application. The fluctuation spectrum for the Gaussian regime in the planar conductivity keeps the three dimensional character. However, filamentary fluctuations are observed along the c-axis above the Ginzburg temperature. Our results for the out-of-plane fluctuation conductivity in YBCO suggest that the c-axis transport is predominantly coherent in this system.
ISSN:1434-6028
1434-6036
DOI:10.1140/epjb/e2011-20527-9