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Title: Morphotropy, isomorphism, and polymorphism of Ln{sub 2}M{sub 2}O{sub 7}-based (Ln = La-Lu, Y, Sc; M = Ti, Zr, Hf, Sn) oxides

Structural studies of compounds of variable composition and measurements of their conductivity have made it possible to identify new oxygen-ion-conducting rare-earth pyrochlores, Ln{sub 2}Ti{sub 2}O{sub 7} (Ln = Dy-Lu) and Ln{sub 2}Hf{sub 2}O{sub 7} (Ln = Eu, Gd), with intrinsic high-temperature oxygen ion conductivity (up to 1.4 Multiplication-Sign 10{sup -2} S/cm at 800 Degree-Sign C). Twenty six systems have been studied, and more than 50 phases based on the Ln{sub 2}M{sub 2}O{sub 7} (Ln= La-Lu; M = Ti, Zr, Hf) oxides have been synthesized and shown to be potential oxygen ion conductors. The morphotropy and polymorphism of the Ln{sub 2}M{sub 2}O{sub 7} (Ln = La-Lu; M = Ti, Zr, Hf) rare-earth pyrochlores have been analyzed in detail for the first time. Thermodynamic and kinetic (growth-related) phase transitions have been classified with application to the pyrochlore family.
Authors:
 [1]
  1. Russian Academy of Sciences, Semenov Institute of Chemical Physics (Russian Federation)
Publication Date:
OSTI Identifier:
22121695
Resource Type:
Journal Article
Resource Relation:
Journal Name: Crystallography Reports; Journal Volume: 58; Journal Issue: 4; Other Information: Copyright (c) 2013 Pleiades Publishing, Ltd.; http://www.springer-ny.com; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRYSTAL GROWTH; HAFNIUM OXIDES; OXYGEN IONS; PHASE TRANSFORMATIONS; PYROCHLORE; RARE EARTH COMPOUNDS; TIN OXIDES; TITANIUM OXIDES; ZIRCONIUM OXIDES