Stabilization of superconducting phases in thallium-barium-copper oxide system by fluorine substitution [TlBa[sub 2]CuO[sub 5[minus]x]F[sub x]]

Journal Article · Tue Feb 01 00:00:00 EST 1994 · Materials Research Bulletin; (United States)

DOI:https://doi.org/10.1016/0025-5408(94)90131-7· OSTI ID:7284120

Subramanian, M A ^[1]

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1. Dupont Co., Wilmington, DE (United States). Central Research and Development

Partial substitution of oxygen by fluorine in TlBa[sub 2]CuO[sub 5] has been achieved by heating Tl[sub 2]O[sub 3], BaO[sub 2], BaO and CuO under one kbar external pressure using TlF as a source for fluorine. A single phase region exists for 0.1 [le] x [le] 0.5 and the X-ray powder diffraction data indicated a tetragonal structure (space group: P4/mmm) for all the compounds. The in-plane Cu-O distance calculated from the a-lattice parameter showed a systematic increase as x was varied from 0.1 to 0.5. This is due to an increase in the formal oxidation state of copper as F[sup 1[minus]] substitutes for O[sup 2[minus]] in the 1201-type structure. The c-lattice parameter also showed a slight increase, as the fluorine content in the reaction mixture is increased. Superconductivity is observed for x values within the range 0.1 to 0.6 with transition temperatures in the range 35--75 K.

• OSTI ID: 7284120
• Journal Information: Materials Research Bulletin; (United States), Vol. 29:2; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
CRYSTAL STRUCTURE
SUPERCONDUCTIVITY
COPPER OXIDES
FLUORINE
METALLURGICAL EFFECTS
THALLIUM OXIDES
LATTICE PARAMETERS
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
HALOGENS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
THALLIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360207 - Ceramics
Cermets
& Refractories- Superconducting Properties- (1992-)