Phase formation in a Bi-Sr-Ca-Cu oxide superconductor

Abstract
The formation of different superconducting phases in the Bi‐Sr‐Ca‐Cu‐oxide system sensitively depends on the preparation procedures, particularly the firing temperatures. The tangled x‐ray powder diffraction patterns of coexisting Bi2Sr2CaCu2Oy and Bi2Sr2Ca2Cu3Oy have been completely identified. The basic unit cells are of approximate tetragonal symmetry. The lattice constants of the latter have been determined to be 5.40×5.40×37.09 Å3.