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Oxide-ion conduction in anion-deficient double perovskites, $Ba_2 BB'O_{5.5} (B = Li, Na; B' = Mo, W, Te)$

Thangadurai, V and Shukla, AK and Gopalakrishnan, J (1997) Oxide-ion conduction in anion-deficient double perovskites, $Ba_2 BB'O_{5.5} (B = Li, Na; B' = Mo, W, Te)$. In: Solid State Ionics, 104 (3-4). pp. 277-283.

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Abstract

We have investigated the oxide-ion conduction of anion-deficient double perovskites of the formula, $Ba_2 BB'O_{5.5} (B = Li, Na; B' = Mo,W, Te)$, in relation to the parent oxides, $Ba_2 BB'O_6 (B = Ca)$. Powder XRD and $^7Li/^{23}$ Na MAS NMR spectra indicate that the oxygen vacancies are not ordered in the $Ba_2 BB'O_{5.5}$ oxides. Anion-deficient oxides show appreciably higher conductivities than the parent stoichiometric oxides. The highest oxide-ion conductivity of $\sim 10^{-2} S/ cm$ at $700^oC$ in this series is exhibited by $Ba_2 NaMoO_{5.5}$. A smooth conductivity transition around $350^oC$ as indicated by a discontinuity in the Arrhenius plots of the molybdenum compounds has been ascribed to a change-over from a two-dimensional to bulk (three-dimensional) oxygen vacancy migration in these oxides.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Elsevier.
Keywords: Perovskites;Oxide-ion conductivity;Solid oxide fuel cell
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Depositing User: Anka Setty
Date Deposited: 12 Apr 2007
Last Modified: 19 Sep 2010 04:36
URI: http://eprints.iisc.ac.in/id/eprint/10379

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