Impact of acceptor-type substitution on electrical transport properties of zircon-type EuVO4

authors	Gayathri, TH; Yaremchenko, AA; Zakharchuk, K; Abhilash, P; Ananthakumar, S
nationality	International
journal	JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
author keywords	Vanadate; Zircon; Thermal expansion; Electrical conductivity; Ionic conductivity
keywords	RARE-EARTH ORTHOVANADATES; HYDROTHERMAL SYNTHESIS; ELECTRONIC-PROPERTIES; THERMAL-EXPANSION; NANOPARTICLES; CA; CONDUCTIVITY; STABILITY; LAVO4; CEVO4
abstract	Magnesium-substituted europium vanadate ceramics, MgxEuVO4 +/- delta (x=0-0.5), were prepared by solid state method and characterized by XRD, SEM/EDS, dilatometry, UV-vis spectroscopy, impedance spectroscopy, and measurements of oxygen-ion transference numbers ((t) over bar (0)). Magnesium was found to substitute preferentially into vanadium sublattice of zircon-type EuVO4 with limited solubility of 5 at.%. Additions of magnesium increase slightly coefficients of thermal expansion (3.2-6.0 ppm/K at 150-400 degrees C) and have negligible effect on the optical properties. Undoped EuVO4 is predominantly an oxygen-ionic conductor with (t) over bar (0) = 0.96-0.99 at 700-900 degrees C under oxidizing conditions. Acceptor-type substitution suppresses total conductivity and oxygen-ionic transport. The variations of electrical transport properties are discussed in terms of interstitial oxygen diffusion in the parent EuVO4 and oxygen vacancy diffusion in Mg-substituted vanadate. Humidified atmosphere has negligible impact on the electrical properties of substituted ceramics but results in increased electrical conductivity of EuVO4 indicating a protonic contribution to the total electrical transport. (C) 2017 Elsevier Ltd. All rights reserved.
publisher	ELSEVIER SCI LTD
issn	0955-2219
year published	2018
volume	38
issue	1
beginning page	145
ending page	151
digital object identifier (doi)	10.1016/j.jeurceramsoc.2017.07.013
web of science category	Materials Science, Ceramics
subject category	Materials Science
unique article identifier	WOS:000414117500016