Neutron-diffraction study of Tl sub 2 Ba sub 2 CuO sub 6+. delta. with various Tc 's from 0 to 73 K

Journal Article · Fri Nov 30 23:00:00 EST 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.10165· OSTI ID:5964157

Shimakawa, Y; Kubo, Y; Manako, T; Igarashi, H ^[1]; Izumi, F ^[2]; Asano, H ^[3]

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1. Fundamental Research Laboratories, NEC Corporation, 4-1-1 Miyazaki, Miyamae-ku, Kawasaki 213 (Japan)
2. National Institute for Research in Inorganic Materials, 1-1 Namiki, Tsukuba 305 (Japan)
3. Institute of Materials Science, University of Tsukuba, Tennodai, Tsukuba 305 (Japan)

We refined the crystal structures of four pseudotetragonal samples of Tl{sub 2}Ba{sub 2}CuO{sub 6+{delta}} with {ital T}{sub {ital c}}'s of 0 (metallic), 48, 58, and 73 K by Rietveld analysis of time-of-flight neutron-powder-diffraction data. The presence of excess oxygen atoms located at an interstitial site between double TlO layers was confirmed. The change in oxygen content and the corresponding one in hole carrier concentration in this compound are caused by incorporation and release of the excess oxygen, whose amount is about 0.1 per formula unit for the metallic nonsuperconducting sample. The highest {Tc} value of about 85 K in Tl{sub 2}Ba{sub 2}CuO{sub 6+{delta}} is achieved in the absence of excess oxygen. As the oxygen content is decreased, the {ital c} value increases, and apical O{sup 2{minus}} ions go away from the CuO{sub 2} layer, while Ba{sup 2+} ions approach it. It was also suggested that about 5% of a Tl site is substituted by Cu. A significant portion of hole carriers in this compound is attributed to substitution of Cu for Tl and incorporation of excess oxygen.

• OSTI ID: 5964157
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:16; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL STRUCTURE
DIFFRACTION
HIGH-TC SUPERCONDUCTORS
LOW TEMPERATURE
MINERALS
NEUTRON DIFFRACTION
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PEROVSKITE
PEROVSKITES
PHYSICAL PROPERTIES
SCATTERING
STOICHIOMETRY
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
THALLIUM COMPOUNDS
THALLIUM OXIDES
THERMODYNAMIC PROPERTIES
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE