Nature of the Transient BaF2-Related Phases in the "BaF₂" Processing of Ba₂YCu₃O_7-x Superconductors

Journal Article · Sun Jan 01 04:00:00 EST 2006 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.2184757· OSTI ID:930732

Wong-Ng, W. ^[1]; Levin, I. ^[1]; Cook, L. P. ^[1]; Feenstra, Roeland ^[2]

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1. National Institute of Standards and Technology (NIST)
2. ORNL

Transient BaF{sub 2}-based oxyfluoride phases are thought to play a critical role in the formation of the c-textured Ba{sub 2}YCu{sub 3}O{sub 7-x} layers of coated conductors. In situ high-temperature x-ray diffraction from the precursor films containing pure BaF{sub 2} as well as pseudobinary BaF{sub 2-Y}, BaF{sub 2-}Cu, and Y-Cu mixtures and heat treated in water vapor under reduced conditions revealed that the transient BaF{sub 2}-based superstructures, similar to those observed during formation of Ba{sub 2}Cu{sub 3}O{sub 7-x}, develop even from the pure BaF{sub 2} precursor. These superstructures results from the dissolution of oxygen in BaF{sub 2} leading to formation of the oxyfluoride phase, Ba(F{sub 2-2x}{open_square}{sub x})O{sub x}, with an ordered arrangement of O, F, and F vacancies.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: OE USDOE - Office of Electric Transmission and Distribution
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 930732
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Vol. 88; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM COMPOUNDS
BARIUM OXIDES
COPPER OXIDES
FABRICATION
KINETICS
OXYFLUORIDES
REACTION INTERMEDIATES
SUPERCONDUCTORS
VACANCIES
YTTRIUM OXIDES