Transverse resistance of YBa2Cu3O7−δ single crystals.

Measured is the transverse electrical resistance of YBa 2 Cu 3 O 7− δ single crystals with different oxygen deficiency values ( δ ) in the temperature range T c − 300 K. The experimental data are approximated by an empiric expression accounting for the fluctuation conductivity near T c and the semiconductor-like resistance regime. Our analysis of the concentration dependences of the fitting parameters, in particular, reveals that the resistance temperature dependence is largely affected by the sample's non-homogeneity. The latter, in turn, causes a T c anisotropy and variable-range hopping conductivity between different phases. The deduced maximal values of the basal-plane coherence length, ξ xy (0), are comparable with those for low-temperature superconductors. [ABSTRACT FROM AUTHOR]