Materials Science Forum, Vol.517, 13-16, 2006
Effects of annealing on phase formation and critical current density of dip-coated Tl0.5Pb0.5Sr1.8Yb0.2CaCu2O7 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 J(c) 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 I-c and J(c) with the number of tapes core. The highest J(c) of 521 A/cm(2) was observed for the 4-core tapes annealed at 870 degrees 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 J(c) of the tapes may be due to the lack of texture in the tapes core as revealed by SEM.