EXAFS Study on the Local Structure of Cu in Bi-Pb-Sr-Ca-Cu-O Systems

Abstract
We have conducted an EXAFS study of two kinds of Pb-added Bi-Sr-Ca-Cu-O superconductors with different compositions having different T c. Copper in the specimen, which mainly consists of the high T c phase (Bi2Sr2Ca2Cu3O y ), has nearly the same coordination number as that of the specimen which has a nearly equal amount of the high T c phase and the low T c phase (Bi2Sr2CaCu2O y ). The former specimen showed a smaller Debye-Waller parameter of in-plane Cu-O bonds than did the latter specimen, both at room temperature and at 77 K.