Effects of Annealing on Phase Formation and Critical Current Density of Dip-Coated Tl_0.5Pb_0.5 Sr_1.8Yb_0.2CaCu₂O₇ Superconducting Tapes

In this study, single-core and multi-core Tl1212 tapes were fabricated from Tl-1212 superconducting powder of Tl0.5Pb0.5Sr1.8Yb0.2CaCu2O7 starting composition derived by conventional solid state synthesis. Single core tapes showed maximum Jc and enhanced 1212 phase formation were achieved for tapes annealed at a higher temperature for a longer duration. Multi core tapes showed a general increase in Ic and Jc with the number of tapes core. The highest Jc of 521 A/cm2 was observed for the 4-core tapes annealed at 870 °C for 90 minutes. The initial drastic drop of the tapes Jc in low magnetic fields (≤1T) indicates limitation on tapes performance by weak links. The low Jc of the tapes may be due to the lack of texture in the tapes core as revealed by SEM.