Modified synthesis route to achieve Sr substituted Cu0.5Tl0.5-1234 superconductor phase

Abstract

A modified synthesis route to prepare Cu0.5Tl0.5Ba2Ca3Cu4O12-y superconductor is proposed. In this modified approach a pure Cu0.5Tl0.5Ba2Ca3Cu4O12-y superconducting phase is achieved at normal pressure. The charge reservoir layer of Cu0.5Tl0.5-1234 superconductor is also modified by substituting Sr at Ba site in 0, 0.15, 0.25 and 0.35 percentages. The substitution of smaller sized Sr is resulted in the decrease of c-axis lattice parameter, which can be resulted in enhanced interlayer coupling strength. The fourier transform infrared spectroscopy also confirms the Sr substitution at Ba site. The superconductivity critical temperature is increased with the increase of Sr content upto x = 0.25, which is then decreased for x = 0.35. The analysis of excess conductivity in the light of Aslamazov-Larkin and Lawrance-Donaich shows that the crossover temperatures such as critical region-3D, 3D-2D and 2D-SWF are shifted to lower temperature with the increase of Sr content; similar is the case with c-axis coherence length. However, the interlayer coupling parameter is increased with the increase of Sr content upto x = 0.35, which shows the enhancement of interlayer coupling due to smaller sized Sr at Ba site. An inverse correlation between critical temperature and c-axis coherence length is also observed from the analysis of fluctuations induced conductivity.