Defect driven ferromagnetism in SnO2: a combined study using density functional theory and positron annihilation spectroscopy

Room temperature ferromagnetic ordering has been observed in a high purity polycrystalline SnO 2 sample due to irradiation of 96 MeV oxygen ions. Ab initio density functional theory calculation indicates that tin vacancies are mainly responsible for inducing the magnetic moment in SnO 2 whereas oxygen vacancies in SnO 2 do not contribute any magnetic moment. Positron annihilation spectroscopy has been employed to characterize the chemical identity of irradiation generated defects in SnO 2 . Results indicate the dominant presence of Sn vacancies in O ion irradiated SnO 2 . The irradiated sample turns out to be ferromagnetic at room temperature. Room temperature ferromagnetic ordering has been observed in polycrystalline SnO 2 . Defect characterization by positron annihilation technique and ab initio calculation indicates that tin vacancies are mainly responsible for inducing magnetic moment in oxygen irradiate SnO 2 .