Analysis of fluctuation conductivity of YBa2Cu3O7-delta-PrBa2Cu3O7-delta superlattices

The fluctuation-induced conductivity measured on YBa2Cu3O7-deltaPrBa2Cu3O7-delta superlattices (SL) is analyzed using various theoretical models describing weak fluctuations in layered superconductors and considering both Aslamazov-Larkin (AL) and Maki-Thompson (MT) terms. From the analysis xi(c)(0) = 1.6+/-0.1 Angstrom and tau(phi)(100 K)similar or equal to 3 x 10(-13) s in clean limit are derived for the interlayer coherence length and temperature-dependent phase-relaxation time, respectively. Large tau(phi) values and AL-MT crossover revealed for all samples studied are attributed to the two-dimensional electronic state nature of SL above the crossover temperature. Possible mechanisms of charge scattering in high-T-c superconductors are also discussed.