Synthesis of superconducting phase-pure YBa sub 2 Cu sub 4 O sub 8
Solid state reaction of appropriate amounts of Y{sub 2}O{sub 3}, BaCO{sub 3}, and CuO for 2 h at 800{degree}C in flowing oxygen with a total pressure of 2.7 {times} 10{sup 2} Pa (2 mm Hg), followed by cooling and annealing at 750{degree}C for 10 h in oxygen at ambient pressure, has produced orthorhombic YBa{sub 2}Cu{sub 4}O{sub 8} ( 124'') as the main phase with YBa{sub 2}Cu{sub 3}O{sub x}( 123'') as a impurity phase. The phase purity improved considerably and nearly phase-pure 124 was obtained upon annealing the as-calcined powder in oxygen at 800{degree}C for 24 h under ambient pressure. Magnetization measurements performed using a low-field SQUID magnetometer showed superconducting transition temperature of 80 K. 20 refs., 5 figs., 1 tab.
- Research Organization:
- Argonne National Lab., IL (USA)
- Sponsoring Organization:
- DOE/CE; NSF
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 7009731
- Report Number(s):
- CONF-900287-2; ON: DE90010455
- Country of Publication:
- United States
- Language:
- English
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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
ANNEALING
ARGON
BARIUM COMPOUNDS
BARIUM OXIDES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBONATES
CHALCOGENIDES
CHEMICAL REACTIONS
COHERENT SCATTERING
CONCENTRATION RATIO
COOLING
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CURRENT DENSITY
DECOMPOSITION
DIFFRACTION
DIFFUSION
DISPERSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
FLUIDS
GASES
HEAT TREATMENTS
IMPURITIES
MAGNETOMETERS
MASS TRANSFER
MEASURING INSTRUMENTS
MEASURING METHODS
MIXTURES
NONMETALS
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PARTICLES
PERTECHNETATES
PHYSICAL PROPERTIES
POWDERS
PRESSURE EFFECTS
RARE GASES
REFRACTORY METAL COMPOUNDS
SAMPLING
SCATTERING
STOICHIOMETRY
SUPERCONDUCTIVITY
SYNTHESIS
TECHNETIUM COMPOUNDS
TECHNOLOGY ASSESSMENT
THERMAL ANALYSIS
TRANSITION ELEMENT COMPOUNDS
VERY HIGH TEMPERATURE
X-RAY DIFFRACTION
YTTRIUM COMPOUNDS
YTTRIUM OXIDES