材料期刊网

The defect structures and the electron paramagnetic resonance parameters for the substitutional Mo(5+) centers in rutile type SnO(2), TiO(2) and GeO(2) crystals are theoretically investigated from the perturbation formulas of these parameters for a 4d(1) ion in rhombically compressed octahedra. The [MoO(6)](7-) clusters suffer the Jahn-Teller effect and transform the ligand octahedra from original elongation on host tetravalent sites to compression in the impurity centers, with additional smaller rhombic (perpendicular) distortions when compared with those in the hosts. The defect structures and the importance of the ligand contributions are discussed.