Bright-field phase contrast electron microscope images of chromia-doped rutiles have been used to study the size and distribution of small defect clusters in specimens of TiO2, (Ti,Cr)O1.995, and (Ti,Cr)O1.985. Comparisons of observed and measured spot contrast densities, and contrast calculations using computer simulations of the defect structures, lead to the conclusion that the smallest clusters observed contained ∼32 Cr3+ cations. Larger clusters occurred with increasing frequency for higher dopant levels, which is consistent with increased interaction and aggregation of traditional or reconstructed small defects (e.g., Cr3+ interstitials or charge-compensated oxygen vacancies).
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry