The electrical conductivity of In2O3-ZrO2 as well as ln2O3 solid solutions doped with SnO2, CeO2, Nb2O5, Pr6O11, and MgO is investigated, in the temperature range between room temperature and 1300°C, and in the oxygen partial pressure range between 5 X 10-5 and 1 atm. In2O3 doped with ZrO2 is an electronic conductor, while ZrO2 doped with ln2O3 is an oxygen-ionic conductor. The two-phase material of the cubic (fcc) ZrO2+ cubic (bcc) ln2O3 solid solutions is a 3-dimensional composite of ionic and electronic conductors. The single-phase ln2O3 doped with ZrO2 is an electronic conductor with a conductivity up to 7 X 104Sm-1 in air. Two maxima in electrical conductivity are found, one in the two-phase region and one in the ln2O3 single-phase region. Lattice defects responsible for electronic conduction in pure and doped ln2O3 are discussed. The defect models for ln2O3 doped with ZrO2 are proposed, and the Kroger-Vink diagram is constructed. The metastable solubility of dopants in ln2O3 due to the slow phase separation kinetics influences the electronic conductivity. ZrO2 is a most effective donor for increasing electronic conductivity of ln2O3, among hypervalent metal oxides including SnO2, Nb2O5; and CeO3.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry