Thermodynamic fluctuations in the 110-K Bi-Sr-Ca-Cu-O superconductor: Evidence for two-dimensional behavior

Abstract
Measurements of the excess conductivity above the superconducting transition for the 110-K phase of the Bi-Sr-Ca-Cu-O compound are reported. The data are very well described in terms of the classic theory of thermodynamic fluctuations in a two-dimensional superconductor. The results are discussed and compared with previous observations on the YBa2 Cu3 O7 compound, where three-dimensional superconductivity was found.