Preparation and properties of superconducting La/sub 1+//sub x/Ba/sub 2-//sub x/Cu/sub 3/O/sub y/ (0less than or equal toxless than or equal to0. 5) ceramics sintered in N/sub 2/ gas atmosphere
A study of the preparation and properties of La/sub 1+//sub x/Ba/sub 2-//sub x/Cu/sub 3/O/sub y/ (0less than or equal toxless than or equal to0.5) system was performed on two kinds of samples. One with 0less than or equal toxless than or equal to0.2 was sintered at 970--980 /sup 0/C in N/sub 2/ gas and postannealed at 300 /sup 0/C in O/sub 2/ gas atmosphere and the other with 0less than or equal toxless than or equal to0.5 was sintered at 900 /sup 0/C in N/sub 2/ gas and postannealed under the same conditions. The samples sintered at 970--980 /sup 0/C were orthorhombic and their oxygen content(y) was nearly 6.95, smaller than that of those sintered at 900 /sup 0/C, which was about 7.15. Thermogravimetric study revealed that samples sintered at 900 /sup 0/C contained a large amount of oxygen; the oxygen content was not substantially reduced at elevated temperature, even in N/sub 2/ gas atmosphere. Resistivity and dc magnetic-susceptibility-measurements revealed that the superconducting properties of the samples sintered at 970--980 /sup 0/C were much better than those of the samples sintered at lower temperature. The T/sub c/'s in the La/sub 1+//sub x/Ba/sub 2-//sub x/Cu/sub 3/O/sub y/ system with yapprox. =7.0 decreased linearly from 93 to 80 K with excess La content, x. Differential scanning calorimetry in O/sub 2/ gas atmosphere showed that the orthorhombic-tetragonal structural phase transition temperatures were lowered monotonically from 485 /sup 0/C (x = 0) to 443 /sup 0/C (x = 0.3). We address the effect of La substitution for Ba in LaBa/sub 2/Cu/sub 3/O/sub 7.0/ samples on their superconducting properties.
- Research Organization:
- Central Research Laboratory, Matsushita Electric Industrial Corporation Ltd., Moriguchi, Osaka 570, Japan
- OSTI ID:
- 6183386
- Journal Information:
- Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 39:13; ISSN PRBMD
- Country of Publication:
- United States
- Language:
- English
Similar Records
Oxygen-vacancy ordering in the Ba/sub 2/YCu/sub 3/O/sub 7-//sub x/(0less than or equal toxless than or equal to1) superconducting system
Dependence of T/sub c/ on hole concentration in the superconductors Bi/sub 4/Sr/sub 3/Ca/sub 3-//sub x/Y/sub x/Cu/sub 4/O/sub 16+//sub delta/
Related Subjects
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
ANNEALING
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL STRUCTURE
DIAGRAMS
ELEMENTS
FABRICATION
HEAT TREATMENTS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
NITROGEN
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHASE DIAGRAMS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SINTERING
SUPERCONDUCTORS
SYNTHESIS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE