Composition of superconducting La/sub 2/CuO/sub 4+delta/: A superconductor doped by excess oxygen defects
We have studied mixed-phase samples of bulk La/sub z/CuO/sub 4/ using neutron powder diffraction, thermogravimetric analysis and resistivity measurements. Samples fired at 950/degree/C and slowly cooled form in the K/sub 2/NiF/sub 4/ structure with CuO impurities for z<2 and La/sub 2/O/sub 3/ impurities for z>2. Neither La-vacancies nor stacking defects were found. The bulk resistivity of the samples show semiconducting behavior which is shorted at 38K by small amounts of superconducting material. The superconductivity is due to the presence of an oxygen-rich phase with stoichiometry La/sub 2/CuO/sub 4.08/. The occurrence of superconductivity in pure La/sub 2/CuO/sub 4.08/ with the same T/sub c/ as observed in the doped La/sub 1.85/Sr/sub 0.15/CuO/sub 4/ indicates that the excess oxygen provides the same level of doping as metal-ion substitution. 19 refs., 8 figs., 1 tab.
- Research Organization:
- Argonne National Lab., IL (USA)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 6193884
- Report Number(s):
- CONF-890426-11; ON: DE89013299
- Resource Relation:
- Conference: Spring meeting of the Materials Research Society, San Diego, CA, USA, 24 Apr 1989; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
Similar Records
Synthesis, characterization, phase diagrams and superconducting and normal state magnetic properties of La{sub 2-x}Sr{sub x}CuO{sub 4} (0 {le} x {le} 0.08) and electrochemically oxidized La{sub 2-x}Sr{sub x}CuO{sub 4+{delta}} (0 {le} x {le} 0.33, 0 {le} {delta} {le} 0.12)
Synthesis, characterization, phase diagrams and superconducting and normal state magnetic properties of La2-xSrxCuO4 (0 ≤ x ≤ 0.08) and electrochemically oxidized La2-xSrxCuO4+δ (0 ≤ x ≤ 0.33, 0 ≤ δ ≤ 0.12)
Related Subjects
COPPER OXIDES
SUPERCONDUCTIVITY
LANTHANUM OXIDES
STRONTIUM COMPOUNDS
SUPERCONDUCTORS
STOICHIOMETRY
BOND LENGTHS
DOPED MATERIALS
NEUTRON DIFFRACTION
OXYGEN
POINT DEFECTS
PRESSURE EFFECTS
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIFFRACTION
DIMENSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
LANTHANUM COMPOUNDS
LENGTH
MATERIALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SCATTERING
TRANSITION ELEMENT COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360204 - Ceramics
Cermets
& Refractories- Physical Properties