ANALYSIS OF FLUCTUATION CONDUCTIVITY OF YBA2CU3O7-DELTA-PRBA2CU3O7-DELTA SUPERLATTICES

The fluctuation-induced conductivity measured on YBa2Cu3O7-deltaPrBa2C u3O7-delta superlattices (SL) is analyzed using various theoretical mo dels describing weak fluctuations in layered superconductors and consi dering both Aslamazov-Larkin (AL) and Maki-Thompson (MT) terms. From t he analysis xi(c)(0) = 1.6+/-0.1 Angstrom and tau(phi)(100 K)similar o r equal to 3 x 10(-13) s in clean limit are derived for the interlayer coherence length and temperature-dependent phase-relaxation time, res pectively. 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.