Ferromagnetism was induced in pure TiO2 single crystals by oxygen ion irradiation. The ferromagnetism was observed up to room temperature and was with weak temperature dependence. By combining X-ray diffraction, Rutherford backscattering/channelling, Raman scattering, and electron-spin resonance spectroscopy, superconducting quantum interference device, displacement per atom, the lattice damage accumulation with increasing fluences was measured. A defect complex, i.e., Ti3+ on the substitutional accompanied by oxygen vacancies, was identified in the irradiated TiO2. This kind of defect complex results in a local (TiO6−x) stretching Raman mode. It was shown that Ti3+ with one unpaired 3d electron provide the local magnetic moments.

Structural and Magnetic Property of Ion Irradiated TiO2 Single Crystals. Ding, B., Xiang, F.: Chinese Journal of Chemical Physics, 2012, 25[1], 19