Crystal structure and potential interstitial oxide ion conductivity of LnNbO4 and LnNb0.92 W0.08O4.04 (Ln = La, Pr, Nd)

Single phase LnNbO4 and LnNb0.92 W0.08O4.04 (Ln = La, Pr and Nd) were prepared via solid state reaction. The crystal structure of the materials has been investigated by X-ray diffraction and Rietveld refinement. PrNb0.92 W0.08O4.04 and NdNb0.92 W0.08O4.04 were found to have the same crystal structure as the parent phases whereas LaNb0.92 W0.08O4.04 has a modulated structure. Electrical conductivity was studied by AC impedance spectroscopy. Substantial improvements in total conductivity were achieved by W doping on the B-site, with LaNb0.92 W0.08O4.04 having the highest overall conductivity of 3.0 × 10− 3 Scm− 1 at 800 °C.