EFFECT OF LEAD ADDITION TO BI-BASED 2222 SUPERCONDUCTING CUPRATES BI2-XPBXSR2(Y,CE)2CU2O10+DELTA

Bi2-xPbxSr2(Y, Ce)2Cu2O10+delta, a new family of lead containing Bi-22 22 compounds has been synthesized and effects of annealing in high pre ssure of oxygen studied. Lead-free Bi2Sr2(Y, Ce)2Cu2O10+delta synthesi zed under flowing oxygen is known to be non-superconducting, but annea ling under high oxygen pressure (100 bar) at 500-degrees-C, induced su perconductivity with T(c)=25 K. On substitution of lead (x > 0.4), the superconductivity appears even in samples synthesized under flowing o xygen (1 bar). T(c) increases with oxygen annealing pressure for all c ompositions, and it also increases with Pb content at a given oxygen p ressure. These findings are discussed.