Identification of the Superconducting Phase in the Bi-Ca-Sr-Cu-O System

Abstract

In order to identify the superconducting phase in the Bi-Ca-Sr-Cu-O system, phase search experiments were performed. The results of power X-ray study, EPMA study, specific gravity measurements and oxygen analysis revealed that the compound having the composition Bi 2 (Ca, Sr) 3 Cu 2 O 9 or Bi 2 (Ca, Sr) 3- Δ x Cu 2 O 9- Δ y is responsible for the high- T c superconductivity. Two possible structure models, which are closely related to the structure of the bismuth titanate Bi 4 Ti 3 O 12 , are proposed for this compound.