Crossover between Aslamazov-Larkin and short-wavelength fluctuation regimes in high-temperature-superconductor conductivity experiments
M. R. Cimberle, C. Ferdeghini, E. Giannini, D. Marré, M. Putti, A. Siri, F. Federici, A. Varlamov
Physical Review B (Condensed Matter)
We present paraconductivity (AL) measurements in three different high temperature superconductors: a melt textured YBa_2Cu_3O_7 sample, a Bi_2Sr_2CaCu_2O_8 epitaxial thin film and a highly textured Bi_2Sr_2Ca_2Cu_3O_10 tape. The crossovers between different temperature regimes in excess conductivity have been analysed. The Lawrence-Doniach (LD) crossover, which separates the 2D and 3D regimes, shifts from lower to higher temperatures as the compound anisotropy decreases. Once the LD crossover
... overcome, the fluctuation conductivity of the three compounds shows the same universal behaviour: for ϵ = T/T_c > 0.23 all the curves bend down according to the 1/ϵ^3 law. This asymptotic behaviour was theoretically predicted previously for the high temperature region where the short wavelength fluctuations (SWF) become important.