Effect of Pb-, La- and Ti-substitutions on the microstructure and superconducting properties of Bi-2212/Ag composite tapes

We investigated the effect of Pb-, La- and Ti-substitutions on the microstructure and superconducting properties of Bi-2212/Ag composite tapes. Ti-substituted tapes were more poorly aligned than Pb- and La-substituted tapes. Transition temperature (T/sub c/) could be achieved above 80 K by Pb- and La-substitutions, while T/sub c/ decreased below 80 K by Ti-substitution. Transport critical current density (J/sub c/) values were below 10 kA/cm/sup 2/ for the Pb- and Ti-substituted tapes, while the La-substituted tapes showed highest J/sub c/ values of 150 kA/cm/sup 2/. The magnetically determined irreversibility field (B/sub irr/) was not improved by substitution. This was independent of elements substituting.