 High temperature crossover in paraconductivity of granular Y1Ba2Cu3O7-yAusloos, Marcel  ; Gillet, François ; et alin Zeitschrift für Physik. B, Condensed Matter (1991), 84(1), 13-16 We have examined the deviation from linearity of the temperature dependence of the electrical resistivity of a YBaCuO ceramics. We have observed at high temperature a crossover behavior toward a ... [more ▼] We have examined the deviation from linearity of the temperature dependence of the electrical resistivity of a YBaCuO ceramics. We have observed at high temperature a crossover behavior toward a logarithmic temperature dependence at lower temperature. It seems relevant to attribute the origin of such a term to a pair breaking mechanism contribution, thus to give a lower bound to the existence of superconductivity fluctuations onset temperature. Our findings also implies that carriers are bosons above T(c). [less ▲] Detailed reference viewed: 4 (0 ULg)Superconductivity fluctuations in Bi(Pb) based granular ceramics superconductors: evidence for fractal behaviorAusloos, Marcel ; ; et alin Zeitschrift für Physik. B, Condensed Matter (1991), 83(3), 355-359 We report precise measurements of the electrical resistivity in three different Bi(Pb) based granular ceramics superconductors. We show that a single critical exponent (5/6) describes the ... [more ▼] We report precise measurements of the electrical resistivity in three different Bi(Pb) based granular ceramics superconductors. We show that a single critical exponent (5/6) describes the superconductivity fluctuations. Such a critical exponent indicates a fractal behavior of the superconducting path. Our results thus indicate a strict two dimensional fluctuation percolation set (below the superconductivity onset temperature 195 K down to T(c)), and provide some proof for Tarascon et al. "shell conductivity path" hypothesis. We estimate the shell thickness to be of the order of 10 angstrom. [less ▲] Detailed reference viewed: 3 (0 ULg) |
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