Study of electrical conductivity of Ca-substituted La2Zr2O7

• 98% of theoretical density is obtained in reducing atmosphere at only 1400 °C.
• Electrical conductivity is dependent on nature of moving charged species.
• Electrical conductivity is dependent on defect sites within the material.
• Electrical conductivity decreases due to excess Ca doping.

The electrical conductivities of La2−xCaxZr2O7−δ (0 ≤ x ≤ 0.07) have been studied in air, and both moist and dry reducing atmosphere (5% H2 in Ar) in the temperature range between 550 °C and 850 °C. The powders are prepared by combustion synthesis technique. The electrical conduction mechanism of the sintered samples in various atmospheres is explained with respect to activation energy and defect sites formed within these materials. The sintered materials of all the compositions follow the linear behaviour in the Arrhenius plot. Maximum electrical conductivity obtained at 850 °C is 0.013 S/cm for La1.95Ca0.05Zr2O7−δ under moist reducing atmosphere and 0.0093 S/cm for La1.93Ca0.07Zr2O7−δ in air atmosphere.

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