An ab initio study was made of pure and doped TiO2 in the rutile and anatase phases. The main purpose was to determine the role played by different defects and different crystal structures in the appearance of magnetic order. The calculations were performed for varying impurity and vacancy concentrations in both TiO2 structures. For Co impurities the local magnetic moment remained almost independent of the concentration and distribution while for Cu this was not the case, there was magnetism for low concentrations that disappears for the higher ones. Impurity–impurity interactions in both structures favor linear ordering of them. Magnetism in undoped samples appears for certain vacancy concentrations and structural strain.

The Role of Vacancies, Impurities and Crystal Structure in the Magnetic Properties of TiO2. M.Weissmann, L.A.Errico: Physica B, 2007, 398[2], 179-83