Superconducting Properties of Ta Substituted (Tl1-xTax)(BaSr)CaCu2O7

Abstract

In this research, the effects of Ta substitution on the Tl-based superconducting materials have been investigated. The standard method of solid-state reaction was applied to prepare the (Tl1-xTax)(BaSr)CaCu2O7 superconductors of high temperature with x = 0, 0.4, 0.5 and 0.6. For all samples, temperature dependence measurements versus the electrical resistance demonstrated metallic normal state behavior. The X-ray diffraction measurement indicated coexistence of mixed phase with Tl-1212 as the major phase and Ta2O5 as an impurity for all substitution samples. A fraction with the highest volume of the Tl-1212 phase in Ta substitution samples is in x = 0.4 (67%), 30% comes from Ta2O5 and the other 3 % belongs to the Tl-1201. All samples with Ta substitution (x ≥ 0.4) showed decreased in Tc onset , Tc zero and Tp . The discussion on the effects of Ta2O5 in the Tl(BaSr)CaCu2O7 superconductors are also provided.