Paraconductivity analysis for superconducting Bi-Sr-Ca-Cu-O whiskers

By means of the paraconductivity analysis, we characterize superconducting Bi2Sr2CaCu2 O8+d whiskers which show a sharp resistive transition correspon ding to the 2223 phase while identified to be mostly in the 2212 phase (99% or more) from XRD and SQUID measurements. The paraconductivity along the a -axis follows the behavior of the Aslamazov-Larkin theory, showing a dimens ional crossover from OD to 1D near T-C. This implies that small islands of the 2223 phase distributed randomly in the 2212 phase could form quasi-1D d imensional percolation structure just above T-C. (C) 2000 Elsevier Science B.V. All rights reserved.