Fergusonite-type CeNbO4+δ : single crystal growth, symmetry revision and conductivity
Bayliss, Ryan D.
Pramana, Stevin S.
White, Andrew J. P.
Skinner, Stephen J.
White, Timothy John
Date of Issue2013
School of Materials Science and Engineering
Large fergusonite-type (ABO4, A=Ce, B=Nb) oxide crystals, a prototype electrolyte composition for solid oxide fuel cells (SOFC), were prepared for the first time in a floating zone mirror furnace under air or argon atmospheres. While CeNbO4 grown in air contained CeNbO4.08 as a minor impurity that compromised structural analysis, the argon atmosphere yielded a single phase crystal of monoclinic CeNbO4, as confirmed by selected area electron diffraction, powder and single crystal X-ray diffraction. The structure was determined in the standard space group setting C12/c1 (No. 15), rather than the commonly adopted I12/a1. AC impedance spectroscopy conducted under argon found that stoichiometric CeNbO4 single crystals showed lower conductivity compared to CeNbO4+δ confirming interstitial oxygen can penetrate through fergusonite and is responsible for the higher conductivity associated with these oxides.
Journal of solid state chemistry
© 2013 Elsevier. This is the author created version of a work that has been peer reviewed and accepted for publication by Journal of Solid State Chemistry, Elsevier. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: http://dx.doi.org/10.1016/j.jssc.2013.06.022.