Electrical conductivity of 5mol.% Yb2O3 and 5mol.% Gd2O3 co-doped Sm2Zr2O7

Abstract: Sm2Zr2O7 co-doped with and without 5mol.% Yb2O3 and 5mol.% Gd2O3 were prepared by a pressureless-sintering method at 1973K for 10h in air. The relative density, structure and electrical conductivity were investigated by the Archimedes method, X-ray diffraction, scanning electron microscopy and impedance spectra measurements. Both Sm2Zr2O7 and (Sm0.9Gd0.05Yb0.05)2Zr2O7 ceramics exhibit a single phase of pyrochlore-type structure. The grain conductivity, grain-boundary conductivity and total conductivity obey the Arrhenius relation, respectively, and gradually increase with increasing temperature from 723 to 1173K. (Sm0.9Gd0.05Yb0.05)2Zr2O7 ceramic is the oxide-ion conductor in an oxygen partial pressure range of 1.0×10−4 to 1.0atm at all test temperature levels. The grain conductivity, grain-boundary conductivity and total conductivity of (Sm0.9Gd0.05Yb0.05)2Zr2O7 with dual Yb3+ + Gd3+ doping are higher than those of undoped Sm2Zr2O7 at identical temperature levels. [ABSTRACT FROM AUTHOR]