Highly Conducting Redox Stable Pyrochlore Oxides

A 2 B 2 O 7 complex oxides with the pyrochlore structure feature a wide variety of chemical compositions and corresponding diverse electrical and physical properties. A new pyrochlore, Yb 0.96 Ca 1.04 TiNbO 6.98, is reported and characterized in terms of structural stability and electrical properties. The material is stable to ∼1450 °C in 5% H 2 /N 2 and has a high electronic conductivity in a reducing atmosphere, e.g., 9 S/cm at 800 °C in 5% H 2 /N 2 after high-temperature reduction. Other cation substitutions enhance the low-temperature kinetics of conductivity response to changes in oxygen partial pressure.