Synthesis of Ba sub 2 YCu sub 4 O sub 8 by anionic oxidation-reduction

Journal Article · Wed Nov 01 04:00:00 EST 1989 · Journal of Materials Research; (USA)

DOI:https://doi.org/10.1557/JMR.1989.1289· OSTI ID:5118335

Kourtakis, K; Robbins, M; Gallagher, P K; Tiefel, T ^[1]

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1. AT T Bell Laboratories, 600 Mountain Avenue, Murray Hill, New Jersey 07974-2074 (US)

The superconducting phase Ba{sub 2}YCu{sub 4}O{sub 8} has been synthesized (as a bulk powder) in flowing oxygen. This was achieved by using the anionic oxidation/reduction method (or the SCD method), in which an aqueous solution containing oxidizing (NO{sup {minus}}{sub 3} salts) and reducing components (e.g., acetate salts) is spray dried into an intimate mixture. At 300 {degree}C, an internal exothermic oxidation/reduction reaction completely converts the spray-dried powder into the corresponding mixed oxides in one reaction step. Because the resultant mixed oxide powder is homogeneous on a fine scale, the final oxide phase can subsequently be produced at lower temperatures and shorter reaction times. Using this method, {similar to}93--94% phase pure Ba{sub 2}YCu{sub 4}O{sub 8} (as determined by x-ray diffraction) has been synthesized in flowing oxygen. Pellets of Ba{sub 2}YCu{sub 4}O{sub 8} fabricated from the mixed oxides were prepared and partially sintered by firing at 800 {degree}C in flowing oxygen for 50 hours. Resistivity and magnetic (A.C.) susceptibility measurements show onset {ital T}{sub {ital c}}'s of 82--84 and 72--73 K, respectively.

• OSTI ID: 5118335
• Journal Information: Journal of Materials Research; (USA), Journal Name: Journal of Materials Research; (USA) Vol. 4:6; ISSN JMREE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACETATES
ALKALINE EARTH METAL COMPOUNDS
ANIONS
AQUEOUS SOLUTIONS
BARIUM COMPOUNDS
BARIUM OXIDES
CARBOXYLIC ACID SALTS
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTIONS
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
DIFFRACTION
DISPERSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FABRICATION
HIGH TEMPERATURE
IMPURITIES
IONS
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MIXTURES
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
REDUCTION
SALTS
SCATTERING
SINTERING
SOLUTIONS
SUPERCONDUCTORS
SYNTHESIS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
VERY HIGH TEMPERATURE
X-RAY DIFFRACTION
YTTRIUM COMPOUNDS
YTTRIUM OXIDES