Lattice parameters, composition, and critical temperatures of yttrium barium copper oxide
The relationships between lattice parameters, composition and critical temperatures in orthorhombic yttrium barium copper oxide (YBa[sub 2]Cu[sub 3]O[sub x]) were critically evaluated using both literature values, as well as high precision values determined to develop quantitative relationships between these variables over specified ranges. The extreme size and near singularity of the resulting matrices necessitates the use of a singular-value decomposition approach for a true and unique linear least-squares solution. Traditional least-squares methods using the normal equations were found to fail completely in this present case. FORTRAN-77 computer code was developed to carry out the required mathematical procedures and to achieve a reproducible least-squares solution of specified accuracy. The phenomenological relationship developed was tested experimentally against the measured properties of a specimen of precisely known composition. The mathematically method developed for these calculations and the approach developed for evaluating the role of lattice parameters and composition effects on critical temperatures are directly applicable to all families of high-temperature superconducting materials.
- Research Organization:
- Duke Univ., Durham, NC (United States)
- OSTI ID:
- 7182726
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
CHEMICAL COMPOSITION
COPPER COMPOUNDS
COPPER OXIDES
CRITICAL TEMPERATURE
HIGH-TC SUPERCONDUCTORS
LATTICE PARAMETERS
OXIDES
OXYGEN COMPOUNDS
PHASE STUDIES
PHYSICAL PROPERTIES
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES