Phase separation and superconductivity in La[sub 2]CuO[sub 4+[delta]]: Effects of oxygen diffusion

Conference · Fri Jan 01 04:00:00 EST 1993

OSTI ID:6308604

Reyes, A P; Hammel, P C; Ahrens, E T; Thompson, J D; Canfield, P C; Fisk, Z ^[1]; Schirber, J E ^[2]

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1. Los Alamos National Lab., NM (United States)
2. Sandia National Labs., Albuquerque, NM (United States)

In oxygen-annealed La[sub 2]CuO[sub 4+[delta]] ([delta][approximately]0.03), bulk magnetization measurements show an increase of [approximately]4K in the superconducting T[sub c] when the sample is cooled slowly through a narrow temperature range near 195K. At this temperature, [sup 139]La NQR spectra exhibit a concomitant appearance of an anomalous feature associated with the metallic phase whose spectral weight increases with cooling rate. The data suggests a distribution of local structures and annealing-dependent volume fraction on this part of the sample. Interpretation of these results in terms of oxygen diffusion in a phase separated material is considered and a picture consistent with the observed changes in T[sub c] is obtained. Other possible origins of these anomalies and the role they play in determining the superconducting properties of this system are discussed.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6308604
• Report Number(s): LA-UR-93-2162; CONF-930367--7; ON: DE93016610
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
CHALCOGENIDES
COOLING
COPPER COMPOUNDS
COPPER OXIDES
DIFFUSION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
HIGH-TC SUPERCONDUCTORS
INTERMEDIATE MASS NUCLEI
ISOTOPES
LANTHANUM 139
LANTHANUM COMPOUNDS
LANTHANUM ISOTOPES
LANTHANUM OXIDES
NONMETALS
NUCLEAR QUADRUPOLE RESONANCE
NUCLEI
ODD-EVEN NUCLEI
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHASE STUDIES
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
RESONANCE
STABLE ISOTOPES
SUPERCONDUCTIVITY
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE