Superconducting fluctuation probed by in-plane and out-of-plane conductivities in Tl2Ba2CaCuO8+y single crystals -: art. no. 144502

Extensive measurements of the in-plane and the out-of-plane zero field resistivities [rho(ab)(T,0), rho(c)(T,0)] and the magnetoresistivities [rho(ab)(T,H), rho(c)(T,H)] of high-quality Tl2Ba2CaCu2O8+y single crystals were carried out. The obtained zero field fluctuation conductivities [Deltasigma(ab)(T,0), Deltasigma(c)(T,0)] and fluctuation-induced magnetoconductivities [Deltasigma(ab)(T,H) and Deltasigma(c)(T,H)] were analyzed based on the theory of thermal fluctuations of the superconducting order parameters, originated from fluctuations of the quasiparticle density of states as well as the Aslamazov-Lakin and Maki-Thompson contributions. We observed that Deltasigma(ab)(T,H) and the sign change in Deltasigma(c)(T,H) near T-c could be described adequately only if the density of states contribution was included. The important physical parameters, such as the coherence length (xi), the in-plane scattering time (tau), and the hopping integral (J), obtained during these analyses are compared with the corresponding parameters for other high-T-c materials.