Oxygen Vacancy-Induced Room Temperature Ferromagnetism in Rutile TiO2

As oxygen vacancies play an important role in ferromagnetism of rutile TiO2, a method of γ-ray irradiates rutile TiO2 single crystals was subtly proposed to study the effect of oxygen vacancies on magnetic properties. Remarkably, room temperature ferromagnetism was observed in γ-ray irradiated rutile TiO2 single crystals, and the saturation magnetization is the strongest when dose is 4 × 104 Gy which assigned to ESR results. Since the displacement threshold energy of Ti atom is much bigger than that of O atom, the defects produced by γ-irradiation are mainly oxygen vacancies. After irradiation, XPS, PL spectra indicate the presence of oxygen vacancies(VO), Ti3+, and VO-Ti3+ composite defects.