Influence of As2O3 vapor pressure on phase formation and superconducting properties of Tl-2212 HTS

As-substituted Tl2–xAsxBa2CaCu2O8+δ (Tl-2212) high-temperature superconductor was synthesized using a two-step method. In the first step, the Ba2CaCu2Oy multiphase precursor was prepared via the in situ polymerization method, and in the second step, Tl and As were simultaneously introduced as dopants (x = 0.5–2.0 wt%). The final synthetic step was carried out in a closed quartz tube under an oxygen pressure of 2 atm. The non-substituted sample showed an onset superconducting transition temperature, Tc(onset), of 107 K. The sample doped with 1.5 wt% As showed the highest Tc(onset) ≈ 114.5 K. However, further substitution with 2.0 wt% As led to a decrease in the transition temperature. Notably, the sample dope with 0.5 wt% As displayed a significant enhancement in intergranular critical current densities, surpassing those of the As-free sample. Overall, the results showed that moderate doping with arsenic trioxide (As2O3, x = 0.5–1.5 wt%) enhances the onset critical superconducting transition temperature, while higher doping levels (1.0–2.0 wt%) adversely affect the intergranular critical current density.