Effect of the Ca-doping on the electrical conductivity of oxide ion conductor Yb2Ti2O7

Aus Kompetenzportal
Wechseln zu: Navigation, Suche
Effect of the Ca-doping on the electrical conductivity of oxide ion conductor Yb2Ti2O7
Autor A. V. Shlyakhtina, P. Fedtke, A. Busch, I. V. Kolbanev, T. Barfels, Marion Wienecke, A. E. Sokolov, V. A. Ulianov, V. A. Trounov, L. G. Shcherbakova
In: Solid State Ionics
Ausgabe 179
ISBN/ISSN:
Erscheinungsjahr 2008
Jahrgang
Seitenzahl 1004-1008
Hyperlink http://www.sciencedirect.com/science/article/pii/S0167273808000179
Review anderes

The first results are presented on heterovalent substitution of alkaline-earth cations Ca2+for Yb3+in oxide ion conductor Yb2Ti2O7. (Yb1-xCax)2Ti2O7 (x = 0.05, 0.1) has been synthesized using mechanical activation of the oxides Yb2O3, CaO, TiO2 and subsequently sintering at 1400 °C in air, and their electrical conductivity has been measured from 300 to 950 °C. (Yb0.9Ca0.1)2Ti2O7 synthesized at 1400 °C from a mechanically activated oxide mixture has the highest conductivity among the pyrochlores studied so far: 2 × 10- 2 S/cm at 740 °C, i.e., 0.2 S/cm at 1000 °C. Neutron diffraction data indicate that the Сa2+in (Yb0.9Ca0.1)2Ti2O7 occupies the ytterbium site, leading to the formation of oxygen vacancies in the O2 (48f) site and the presence of oxygens in the O3 (8b) site, normally vacant in ordered pyrochlores. No evidence of Ca substitution on the Ti site has been found.