Synthesis and structure of Tl1-xCuxSr1.6Yb0.4CaCu2O7-δ (x = 0.0-0.6) superconductors / Siti Azwani Yaacob.

In this project, the effects of Cu substitution for Tl in TlSrl212 superconductors have been investigated. The sample have been prepared with nominal starting compositions of Tl1-xCuxSr1.6Yb0.4CaCu2O7-δ (x=0.0-0.6) using conventional solid state synthesis method and under normal pressure technique.XRD analysis of Tl1-xCuxSr1.6Yb0.4CaCu2O7-δ (x=0.0-0.6) series showed 1212 phase as major phase. Temperature dependent electrical resistance measurements on the series showed that the normal state behavior and superconducting properties can be controlled . by adjusting Cu concentration to achieve maximum critical temperature (rc).The best superconducting behavior of the series was observed for Tl0.7Cu0.3Sr1.6Yb0.4CaCu2O7 with zero critical temperature (Tc zero) of 80 K and onset of superconductivity (Tc onset) of 95 K. Superconducting fluctuation behavior has been studied in samples of Cu-substituted Tl1-xCuxSr1.6Yb0.4CaCu2O7-δ (x=0.0-0.3) by electrical resistivity measurements. Analysis of excess conductivity behavior based on Aslamazov-Larkin (AL) theory revealed transition from 2-D to 3-D behavior of the superconducting fluctuation in the mean field region -4< In ε<-2 for sample with Cu content (x=0.0-0.3.The behavior of superconducting fluctuation constant (AL) both 2D and 3D are similar with the amount of Cu substitution and achieve maximum at amount of Cu content (x=0.1) respectively.