Influence of the oxygen partial pressure on the solubility of PbO in the (Bi, Pb)2Sr2CaCu2O8+y superconducting oxides

✍ Scribed by Yutaka Iwai; Yoshiaki Hoshi; Hiroshi Saito; Masasuke Takata

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 374 KB
• Volume: 170
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(90)90330-h

✦ Synopsis

A systematic study of the solubility of PbO in the (Bil _xPbx)2Sr2CaCu208 +y compound at various oxygen partial pressures has been carried out. The solubility was found to increase as the oxygen partial pressure decreased. The change in lattice parameter with PbO concentration supported the solubility data. By annealing the 2212 phase with a large amount of PbO under a high oxygen partial pressure, a secondary phase having an XRD pattern similar to that of Ca2PbO4 was precipitated. Simultaneously, the 2212 phase transformed from a monoclinic (nearly orthorhombic) to a tetragonal structure in the 2212 phase with a small amount of PbO. The annealing effect in the (Bi, Pb)-based superconductor can be explained by the variation of the solubility of PbO due to the oxidation of the Pb 2+ ions, when the secondary phase is assumed to be isostructural with Ca2PbO4.