Magnetism in SrTiO3 before and after UV irradiation

SrTiO3 cubes are synthesized by the composite-hydroxide-mediated approach. The energy gap of the SrTiO3 changes from 3.24 to 3.19 eV, and the light absorption ability increases after UV irradiation. Oxygen vacancies are found in the SrTiO3 cubes, which increase after UV irradiation illustrated by X-ray photoelectron spectroscopy spectra. The SrTiO3 cubes exhibit weak ferromagnetism with the saturation magnetization of 2.00 x 10(-2) emu/g, which increases to 5.10 x 10(-2) emu/g after UV irradiation at room temperature. Calculations based on density functional theory have demonstrated that the ferromagnetism is a result of oxygen vacancies (Vo), due to the fact that the d state of the nearest-neighbor Ti atom is occupied by unpaired electrons around the oxygen vacancy. This work indicates that a new diluted magnetic material of oxygen vacancy rich SrTiO3 can be obtained by UV irradiation. (C) 2015 Elsevier B.V. All rights reserved.