Electrical properties of dense Me-doped bismuth vanadate (Me = Cu, Co) pO(2)-dependent conductivity determined by impedance spectroscopy

Co- and Cu-substituted Bi4V2O11 compounds were synthesised by means of fine reactive powders with a typical d(50) close to 0.5 mum. Appropriate sinter ing conditions resulted in fine and homogeneous microstructure without any cracks related to large grain size. The total electrical conductivity was m easured by complex impedance spectroscopy with respect to temperature, oxyg en partial pressure, thermal history, and nature of dopant. The bulk and th e grain boundary conductivity were also studied for both compounds. No time -dependence and no thermal hysteresis of the total electrical conductivity were observed and a structure dependence of the electrical properties was n oticed. BICUVOX0.10 material can be considered as a pure oxide ion conducto r within the investigated experimental conditions whereas BICOVOX0.10 exhib ited a p-type conductivity contribution to the bulk conductivity with an io nic transference number greater than 0.97. (C) 2001 Elsevier Science Ltd. A ll rights reserved.