Stability of superconducting phases in Bi-Sr-Ca-Cu-O and the role of Pb doping

Journal Article · Fri Sep 01 04:00:00 EDT 1989 · Physical Review (Section) B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.40.5266· OSTI ID:5650440

Dou, S X; Liu, H K; Bourdillon, A J; Kviz, M; Tan, N X; Sorrell, C C ^[1]

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1. School of Materials Science and Engineering, The University of New South Wales, P.O. Box 1, Kensington, New South Wales, Australia 2033 (AU)

The effects of heat treatment, partial oxygen pressure ({ital P}{sub O{sub 2}}), and Pb substitution on the oxygen nonstoichiometry and on the stability of superconducting phases in the Bi-Sr-Ca-Cu-O systems were examined. The Pb substitution promoted and stabilized the 110-K phase, with a reproducible zero resistance at 107 K achieved in Pb-substituted samples. {ital P}{sub O{sub 2}} hardly affects the superconducting transition temperature ({ital T}{sub {ital c}}) in Pb stabilized samples while a large variation of {ital T}{sub {ital c}} in Bi-Sr-Ca-Cu-O systems was observed by changing {ital P}{sub O{sub 2}} from 0.01 to 1.0 atm. The Cu{sup 3+} concentrations determined by a volumetric measurement technique vary little with {ital P}{sub O{sub 2}} over the range studied, so this ion is not critical for superconductivity in Bi-Sr-Ca-Cu-O, as it is in Y-Ba-Cu-O. The higher extra oxygen content obtained from iodometric titration is attributed to the oxygen associated with Bi{sup 5+} ions in Bi-O{sub 2} layers which are not measured by the volumetric method. Such ions result from cationic vacancies. In doped 2:2:2:3 compounds Pb{sup 4+} ions, most likely located in the Bi layers, lower the charge states of both Bi and Cu which are otherwise raised by cationic vacancies.

• OSTI ID: 5650440
• Journal Information: Physical Review (Section) B: Condensed Matter; (USA), Journal Name: Physical Review (Section) B: Condensed Matter; (USA) Vol. 40:7; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
BISMUTH COMPOUNDS
BISMUTH OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL DOPING
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
HEAT TREATMENTS
LEAD ADDITIONS
LEAD ALLOYS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
STABILIZATION
STOICHIOMETRY
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTIVITY
TRANSITION ELEMENT COMPOUNDS