TRANSPORT-PROPERTIES OF YBACUO AND BISRCACUO THIN-FILMS IN THE THERMODYNAMIC FLUCTUATION RANGE

Thin films of YBaCuO have been fabricated by pulsed-laser deposition i n oxygen atmosphere on MgO substrates. Films of the 2223-phase of BiSr CaCuO, stabilized by Pb-addition in the ceramic targets, were prepared by DC-magnetron sputtering. The effect of thermodynamic fluctuations of the superconducting order parameter on the normal state transport p roperties was investigated by measurements of the electrical resistivi ty, the magnetoresistance and the Hall effect. Analyzing the results i n terms of Aslamazov-Larkin and Maki-Thompson theories and their exten sions for 2-dimensional, layered superconductors, we obtain a consiste nt set of parameters from which the c-axis coherence lengths xi(c)(0) = 1.5 angstrom in YBaCuO and xi(c)(0) = 1.7 angstrom in 2223-(Bi,Pb)Sr CaCuO are deduced. A significant contribution from the Maki-Thompson p rocess was found in YBaCuO, but no such effects in the (Bi,Pb)SrCaCuO films.