Experimental study of La/sub 1/Ba/sub 2/Cu/sub 3/O/sub x/

Journal Article · Thu Sep 01 04:00:00 EDT 1988 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.38.4605· OSTI ID:6933621

Song, Y; Golben, J P; Chittipeddi, S; Gaines, J R; Epstein, A J

We have prepared samples in the La/sub 1/Ba/sub 2/Cu/sub 3/O/sub x/ series with superconducting transition temperatures T/sub c/ ranging from 23 to 72 K (onset temperatures from 43 to 88 K). Results from scanning-electron-microscopy characterization, x-ray diffraction analysis, thermogravimetric analysis, the temperature dependence of the resistivity, and temperature dependence of the magnetic susceptibility are presented. The samples with T/sub c/ greater than 50 K are orthorhombic while samples with T/sub c/ less than 50 K show tetragonal structure. The transition temperature is found to depend on the oxygen content x with an apparent peak near x = 7. Our sample with the highest T/sub c/ (72 K) had x = 6.75. As x decreases, so does T/sub c/, reaching 44 K when x = 6.47. For oxygen content greater than 7, T/sub c/ decreases rapidly to a value of 23 K when x = 7.27. The room-temperature resistivity increases systematically from 0.8 to 7.9 m..cap omega.. cm as T/sub c/ decreases from 72 to 27 K. The increase is resistivity in the normal state and the decrease in the resistivity ratio (rho/sub 300 K//rho/sub residual/ are interpreted in terms of disorder in the microscopic structure which suppresses T/sub c/. The magnetic susceptibility of these samples separates into a Pauli susceptibility chi/sub 0/ and a Curie-Weiss susceptibility C/(T-FTHETA), after the core contribution is subtracted. A systematic increase in chi/sub 0/ and a decrease in the Curie constant C has been observed as T/sub c/ varies from 23 to 72 K.

• Research Organization: Department of Physics, The Ohio State University, Columbus, Ohio 43210
• OSTI ID: 6933621
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 38:7; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON MICROSCOPY
ENERGY LEVELS
ENERGY-LEVEL DENSITY
FERMI LEVEL
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
LOW TEMPERATURE
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MEDIUM TEMPERATURE
MICROSCOPY
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SCANNING ELECTRON MICROSCOPY
SCATTERING
SUPERCONDUCTIVITY
TEMPERATURE DEPENDENCE
TETRAGONAL LATTICES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
VERY LOW TEMPERATURE
X-RAY DIFFRACTION