Protons and lattice defects in perovskite-related oxides

Technical Report · Mon Jan 01 00:00:00 EST 1990

DOI:https://doi.org/10.2172/7172698· OSTI ID:7172698

Nowick, A S

The recent work on this project has focused on two perovskite- structured materials: single crystalline KTaO{sub 3} doped with iron-group ions, and ceramic BaCeO{sub 3} doped with Nd, Gd, Sc and Ca. In the case of KTaO{sub 3}, we have shown that protons are introduced into the crystal from H{sub 2}O vapor so that it becomes primarily a protonic conductor. The defect reactions involved have been considered in detail with the aid of EPR and IR measurements. In the study of BaCeO{sub 3}, it was found that the Nd-doped material is an excellent protonic conductor with activation energy for proton hopping of only 0.54 eV. In addition, weight-change measurements were used to determine the amount of water uptake, while Nernst-cell measurements gave values for the transport numbers of oxygen and of protons. In contrast to the case of Nd doping, Gd or Yb-doped material are not protonic conductors. Other studies include those of high-{Tc} superconductors, the first showing a large elastic constant and internal friction anomaly in La{sub 2x}Sr{sub x}CuO{sub 4}, and the second showing under what conditions degradation occurs due to H{sub 2}O and CO{sub 2} annealing treatments. Finally, a study of dielectric loss in Li-borate glasses shows that the dielectric loss peak in glasses widely believed to be due to a bulk phenomenon, is actually an electrode blocking effect.

• Research Organization: Columbia Univ., New York, NY (USA). Henry Krumb School of Mines
• Sponsoring Organization: DOE/ER
• DOE Contract Number: FG02-88ER45341
• OSTI ID: 7172698
• Report Number(s): DOE/ER/45341-3; ON: DE90010957
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
CRYSTAL DEFECTS
CERIUM OXIDES
PEROVSKITES
POTASSIUM OXIDES
TANTALUM OXIDES
HIGH-TC SUPERCONDUCTORS
PROGRESS REPORT
PROTONS
STRONTIUM OXIDES
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARYONS
CERIUM COMPOUNDS
CHALCOGENIDES
CRYSTAL STRUCTURE
DOCUMENT TYPES
ELEMENTARY PARTICLES
FERMIONS
HADRONS
NUCLEONS
OXIDES
OXYGEN COMPOUNDS
POTASSIUM COMPOUNDS
RARE EARTH COMPOUNDS
REFRACTORY METAL COMPOUNDS
STRONTIUM COMPOUNDS
SUPERCONDUCTORS
TANTALUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360204 - Ceramics
Cermets
& Refractories- Physical Properties