Measurement and properties of the oxide ionic conductivity of beta-phase in the binary system of (Bi2O3)(1-x)(Sm2O3)(x)

The tetragonal P-phase in the binary system of (Bi2O3)(1-x)(Sm2O3)(x) was synthesized by solid-state reactions with doping Sm2O3 into the monoclinic Bi2O3, in the stoichiometric ratio of range 0.01 < x < 0.10. X-ray powder diffraction (XRD) data showed that the unit cell parameters of produced tetragonal-type materials increased with the increasing doping of Sm2O3. We have measured the total electrical conductivity (sigma(T)) depending on the temperature and doping concentration. Bi2O3-based ceramic system doped with Sm2O3 showed an oxide anionic-type electrical conductivity which is increased with the increase of the dopant concentration and temperature. In the investigated system, the highest value of conductivity was observed sigma(T) = 0.029 Omega(-1) cm(-1) at 670 degrees C, for the composition of 7 mole% Sm2O3 addition. The phase transition which manifests itself by the jump in the conductivity curves was also verified by DTA measurements which are in good agreement with the observed results of electrical conduction. The electrical conductivity curves of studied materials revealed regular increase with the temperature in the form of the Arrhenius-type conductivity behavior and the activation energies (E-a) were calculated by using these graphs. (C) 2008 Elsevier B.V. All rights reserved.