The effect of O2 pressure on phase formation and superconductivity properties of Tl-based HTS

Thallium-based high-temperature superconductors exhibit excellent superconductivity performance (Tc, Jc). Formation of the Tl-based superconducting materials critically depends on the used precursor and synthesis conditions. In the present investigation, we used the in situ polymerization method for synthesizing high-purity and reaction-ability precursors. We find the critical dependence of Tl-based superconductor phase formation on the quantity of applied oxygen pressure. The experimental results showed that the Tl-1223 phase formed at an oxygen gas pressure at 1 to 2 atm, Tl-2223 phase at 3 atm, and Tl-2212 phase at 4 to 8 atm.