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Cation Deficiency in Bi 2 (Sr,Ca) 3 Cu 2 O 8+ d
Author(s) -
Nomura Shunji,
Yamashita Tomohisa,
Yoshino Hisashi,
Ando Ken
Publication year - 1991
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1991.tb06831.x
Subject(s) - stoichiometry , chemistry , vacancy defect , analytical chemistry (journal) , oxygen , titration , composition (language) , solid solution , alkaline earth metal , chemical composition , oxygen deficiency , ion , lattice constant , inorganic chemistry , crystallography , mineralogy , alkali metal , diffraction , linguistics , philosophy , physics , organic chemistry , optics , chromatography
X‐ray lattice parameter measurements of the Bi 2‐ x (Sr,Ca) 3‐ y Cu 2‐ z O 8+ d system show that a continuously varying solid‐solution cation nonstoichiometry exists within the overall composition ranges x < 0.32, ‐0.2 < y < 0.32, and z < 0.25. A modulated structure along the b axis remains present over these composition ranges. Defects introduced by cation deficiency have been clarified to be vacancies by density measurements. The oxygen content determined by titration decreases proportionately with increasing cation vacancy concentrations. In Bi‐deficient compositions, the interstitial oxygen ion concentration decreased and the oxygen vacancy concentration increased with increasing concentration of Bi vacancies. The critical temperature, T c , shows a maximum value at the stoichiometric cation composition and decreases to a slightly lower (5 to 10 K) constant value across the nonstoichiometric composition region with both increasing alkaline‐earth and Cu deficiency.