Enhanced critical current density in (Bi,Pb)-2223/Ag tapes prepared using precursors calcined in dynamic vacuum with oxygen partial pressure

Superconducting properties of (Bi,Pb)-2223/Ag tapes prepared using four different precursors calcined under different conditions viz. (1) dynamic vacuum with oxygen partial pressure, (2) static vacuum, (3) static air and flowing O2 have been studied. The precursors showed wide variations in their phase assemblage and partial melting temperature. Tapes prepared using them exhibited entirely different properties in terms of phase evolution, microstructure and JC. The precursor calcined in vacuum with oxygen partial pressure yielded the best results with distinctly higher JC. The variation in the tape characteristics brought about by different precursors has been analysed and the importance of dynamic vacuum calcination in oxygen partial pressure has been highlighted.