Determination of oxygen content and cation valences in superconducting Tl-based cuprates by a wet chemical method

Journal Article · Mon May 01 04:00:00 EDT 1995 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.51.12759· OSTI ID:44581

Fukuoka, A; Karppinen, M; Itoh, M; Hamada, K; Yamauchi, H ^[1]

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1. Superconductivity Research Laboratory, ISTEC, 10-13 Shinonome 1-chome Koto-ku Tokyo (Japan)

A wet chemical route based on constant-potential electrolysis and different reactivities of Cu{sup 3+} and Tl{sup 3+} with water is proposed to distinguish the average valences of Cu and Tl in superconducting thallium cuprates. The validity of the method is demonstrated using YBa{sub 2}Cu{sub 3}O{sub {ital y}}, Tl{sub 2}O{sub 3}, and Tl{sub 2}O as reference materials for Cu{sup 3+}, Tl{sup 3+}, and Tl{sup +}, respectively. Furthermore, the oxygen contents and the cation valences have been determined for various Tl-22({ital n}{minus}1){ital n} phases (where {ital n}=1--4). With increasing {ital n} value the Cu valence is found to decrease, while the valence of thallium remains rather constant at ca. +3, regardless of the value of {ital n}. Based on these results, the possible carrier doping mechanisms in the Tl-22({ital n}{minus}1){ital n} phases are discussed.

• OSTI ID: 44581
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 18 Vol. 51; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BARIUM OXIDES
CALCIUM OXIDES
COPPER OXIDES
HIGH-TC SUPERCONDUCTORS
OXYGEN
THALLIUM OXIDES
VALENCE