Influence of Mg2+ ion on the optical and magnetic properties of TiO2 nanostructures: A key role of oxygen vacancy

Over the years, oxide based dilute magnetic semiconductor (DMS) materials have been of great interest due to their potential use in spintronic devices. Among several oxide based DMS materials, TiO2 nanoparticles (NPs) have been considered largely due to their interesting optical and magnetic properties. The effect of Mg doping on intrinsic defect formation (oxygen vacancy) was investigated by UV-vis and PL spectroscopy studies. In particular, 5% Mg-doped TiO2 has promising photocatalytic activity for the degradation of methylene blue (MB) and 4-nitrophenol (4-NP) over the pure and other Mg-doped TiO2 samples. This noteworthy enhanced photo catalytic activity could be attributed to both the effective separation of charge carrier and the strong light absorption ability, resulting from the incorporation of Mg into TiO2 lattice. As compared to pure TiO2 sample, Mg doped TiO2 samples display a remarked increase in saturation magnetization (M-s). Therefore, the combination of PL and magnetic measurements shows the increase of oxygen vacancy due to the Mg doping which plays a key role in the optical and magnetic performances of the TiO2 NPs.