Defect structure and solubility range of gallium-doped cobalt oxide

Article abstract of DOI:10.1002/bbpc.19971010205

The electrical conductivity a of polycrystalline cobalt oxide doped with gallium oxide, CO_1-xGa_21./3O, was measured as a function of temperature (800- 1400°C), oxygen activity (10^-4-0.21) and composition x (0-0.125). The phase boundary of the solid solution as a function of temperature and oxygen activity was ascertained by a well-defined change of the slope in the σ-TArrhenius plot. As a function of Ga₂O₃-content, the electrical conductivity runs through more or less distinct minima at all temperatures and oxygen activities. To explain these dependencies, a defect model was developed, which contains different defect associates and a 4: l-cluster. It emerges from a model in which associated holes contribute to the total conductivity as well as free holes. Due to this fact different mobilities result for the respective holes. VCH Verlagsgesellschaft mbH, 1997.