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Electrical conductivities of ZrO2-Sm2O3 systems containing 10, 20, 30, 40, and 50 mol% of ZrO2 have been measured as a function of temperature and of oxygen partial pressure at temperature from 500 to 1000℃ and oxygen partial pressures from 1 × 10-5 to 1 × 10-1 atm. Plots of log conductivity vs. 1/T are found to be linear with an inflection point at around 650℃ and the temperature dependence of conductivity shows two different defect structures. The conductivities are increased with increasing pressure, slowing a p-type character. The electrical conductivity dependences on PO2 are found to be σ∝PO21/5.3 at 650∼1000℃ and σ∝PO21/6 at 500∼650℃, respectively, The defect structures are Oi" at 650-1000℃ and VSm"' at 500-650℃. The electron hole is main carrier type, however ionic contribution is found at low temperature portion. Ionic contributions increased with the increasing amount of ZrO2 dopant. In 60mol% ZrO2-Sm2O3 system, the conductivity is increased with decreasing oxygen pressure.
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