Superconducting properties of oxygen deficient YBa/sub 2/Cu/sub 3/O/sub 7-delta/

Conference · Mon Feb 01 04:00:00 EST 1988

OSTI ID:7257312

Kwok, W K; Crabtree, C W; Veal, B W; Claus, H

An important and interesting feature of the high temperature superconductor YBa/sub 2/Cu/sub 3/O/sub 7/minus/delta/ is the dramatic effect of oxygen vacancies on its superconducting properties. As oxygen is systematically removed from the structure, the orthorhombic distortion decreases and the system undergoes a structural transition to a tetragonal phase. Simultaneously, T/sub c/ falls monotonically, with superconductivity disappearing at approximately the stoichiometry where the orthorhombic-to-tetragonal structural transition occurs. The curve of T/sub c/ versus delta shows two regions of stable superconductivity where T/sub c/ is not a strong function of delta. For delta near zero, there is a nearly flat region where T/sub c/ is close to 90/degree/K and for .35 < delta <.45 there is a plateau where T/sub c/ remains constant at approximately 60/degree/K. The width of the inductive transition in these two regions is narrow suggesting that the superconductivity is due to a homogeneous well defined phase. In order to investigate the mechanisms and properties of superconductivity in YBa/sub 2/Cu/sub 3/O/sub 7/minus/delta/ it is necessary to characterize and compare the superconducting behavior in these two phases. In this paper we present resistivity and magnetization data from which we determine the upper critical field H/sub c2/ and compare the relative pinning strengths of polycrystalline samples with delta = 0.04 and 0.4. 18 refs., 4 figs.

• Research Organization: Argonne National Lab., IL (USA); Illinois Univ., Chicago (USA). Dept. of Physics
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 7257312
• Report Number(s): CONF-880207-2; CONF-880207-; ON: DE88009969
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
&amp; Refractories-- Structure &amp; Phase Studies
360204* -- Ceramics
Cermets
&amp; Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COMPARATIVE EVALUATIONS
COPPER COMPOUNDS
COPPER OXIDES
CRITICAL FIELD
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
MAGNETIC FIELDS
MAGNETIC FLUX
MAGNETIZATION
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POINT DEFECTS
SUPERCONDUCTIVITY
TETRAGONAL LATTICES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
VACANCIES
YTTRIUM COMPOUNDS
YTTRIUM OXIDES