Superconducting Fluctuations in Polycrystalline Y3Ba5Cu8O18

The Y3Ba5Cu8O18 superconductors are synthesised using the solid state reaction method under different annealing conditions. Structure characterisation using X-ray diffraction shows that the lattice parameters are different from those of the standard YBCO system. The resistivity measurements are performed using the four-probe method in the temperature range from 77 to 300 K. The electrical resistivity indicates the transition temperature T (c) (O-2)=100.2 K and T (c) (air)=92.3 K. Thermal fluctuations were experimentally studied. The correlations of the critical exponents with the dimensionality of the fluctuation system for each Gaussian regime were performed using the Aslamazov-Larkin theory. Near T (c) , a critical regime with a critical exponent of lambda (CR)=0.35 is effectively described by the E-model.