Pseudogap in CdBa2Cu3O7-δ HTSC material

The long-life minima on the ρ(T) dependence (at Tmin1 = 275 K and Tmin2 = 252 K) in CdBa2Cu3O7-δ, (Tc = 86,6 K) have been revealed. It is shown that the observed excess conductivity Δσ(T) around Tmin follows the classic Aslamazov-Larkin fluctuation theory. This suggests that the formation of Cooper electron pairs at T >> Tc in CdBa2Cu3O7-δ, is quite possible. The experimental data are used to calculate coherence lengths ξc(0), 2D-3D crossover temperature Tcr, and interlayer coupling strength. The value and temperature dependence of pseudogap have been calculated for a minimum-free sample which proves to be typical of cuprate NTSC.