Gaussian and Three-Dimensional-XY Scalings and Effects of Disorder in the Fluctuation Magnetoconductivity of Polycrystalline DyBa2Cu3O7-δ

Abstract

Systematic measurements of the fluctuation magnetoconductivity in granular DyBa2Cu3O7–δ in magnetic fields up to 50 kOe are reported. Gaussian and critical scalings are observed in the normal state. In the Gaussian regimes, large intervals corresponding to low‐dimensional fluctuations are evidenced. Below Tc, in the regime describing the approach to the zero‐resistivity state, the fluctuation conductivity diverges as expected in the coherence transition of mesoscopic granular superconductors in low magnetic fields.