Electrical conductivity of defect fluorite-type (Gd_1-xYb_x)₂Zr₂O₇ solid solutions

(Gd_1-xYb_x)₂Zr₂O₇ (0 ≤ x ≤ 1) solid solutions were prepared by pressureless-sintering process at 1973 K to investigate the substitution effect of Yb for Gd on their electrical properties. Electrical conductivity of (Gd_1-xYb_x)₂Zr₂O₇ solid solutions were measured using complex impedance spectroscopy from 673 to 1173 K over a frequency range of 2 Hz to 2 MHz in air. (Gd_1-xYb_x)₂Zr₂O₇ are oxide-ion conductor in the oxygen partial pressure range from 1.0 × 10^-4 to 1.0 atm at all test temperature levels. The measured values of grain conductivity obey the Arrhenius relation. The grain conductivity of (Gd_1-xYb_x)₂Zr₂O₇ increases with increasing temperature. However, the grain conductivity of (Gd_1-xYb_x)₂Zr₂O₇ gradually decreases with increasing ytterbium content at identical temperature levels.