Defect structure and electrical conductivity studies of thulium sesquioxide

초록

The electrical conductivity of thulium sesquioxide has been measured from 400 to 1100°C under oxygen partial pressures (P<inf>o<inf>2</inf> </inf>) of 10-6 to 10-1 atm. Plots of log conductivity vs 1/T at constant P<inf>o<inf>2</inf> </inf> are found to be linear with an inflection point, the activation energies obtained from the slopes being 34.5 kcal/mole in the higher temperature region and 19.3 kcal/mole in the lower temperature region. The P<inf>o<inf>2</inf> </inf> dependencies of the electrical conductivity are found to be linear and closely approximated by σ ∝ P 1 5.3 <inf>o<inf>2</inf> </inf>in the temperature range 600-1100°C and σ ∝ P 1 6.3 <inf>o<inf>2</inf> </inf> in the range 400-600°C. The dominant defect is V<inf>Tm</inf> ' ́' within the temperature region studied, but an ionic contribution exists in the lower temperature region. An interpretation of the conductivity dependences on temperature and P<inf>o<inf>2</inf> </inf> is presented and conduction mechanisms are suggested to account for the data. © 1986.

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