Article révisé par les pairs
|The resistive behavior of single phase bulk Bi2Sr2CaCu2O8+δ superconductors has been studied in a magnetic field in the region between the percolation and superconductivity transitions. The samples used have been prepared by the spray drying technique with Bi2+xSr2-x-yCa2+yCu2O8+ δ for x = y = 0.05 or 0.1 as starting composition. The data analysis when performed in terms of two-dimensional Kosterlitz-Thouless theory leads to remarkable quantitative agreement, confirming the picture of highly two-dimensional behavior of macroscopic fluctuations (of vortex-antivortex depairing type) as discussed and found by Livanov et al. for similar thin films. © 1994.