Study of superconducting fluctuations in the high-temperature superconductors YBCO and BSCCO by magneto-transport measurements

Summary form only given. The contributions of thermodynamic fluctuations of the superconducting order parameter to several components of the normal-state magneto-conductivity tensor were investigated. We present measurements of the electrical resistivity, the Hall effect and the magnetoresistance at temperatures above T/sub c/ in thin films of the high-T/sub c/ superconductors YBa/sub 2/Cu/sub 3/O/sub 7/ and (Bi,Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub x/ with the magnetic field oriented parallel to the c-axis. From an analysis of the results using the theories for thermodynamic fluctuations in layered superconductors of Aslamazov-Larkin and Maki-Thompson type, we obtain a consistent set of parameters. The main results are the coherence lengths along the ab-plane, /spl xi//sub ab/(0) = 1.2 nm (YBCO), /spl xi//sub ab/(0) = 1.65 nm (BSCCO) and parallel to the c-axis, /spl xi//sub c/(0) = 1.5 nm (YBCO), /spl xi//sub c/(0) = 1.4 nm (BSCCO), respectively. Magnetoresistance measurements in fields up to 13 T reveal superconducting fluctuations extending to temperatures as high as 2T/sub c/.