Room-temperature ferromagnetism properties of monoclinic VO2 (M1) nanobelts

Abstract The magnetic properties of monoclinic VO 2 (M1) nanobelts synthesized by the hydrothermal method are investigated. The VO 2 (M1) nanobelts exhibit ferromagnetism at room temperature, which disagrees with previous literatures. The excessive oxygen vacancies induce the ferromagnetic nature of VO 2 (B) nanobelts, which is attributed to the fact that the Bader charge of V atom changes from +2.34 to +1.84 (V +4 to V +3 ) based on the calculations by using density functional theory (DFT). The calculations indicate that oxygen vacancy may induce the presence of V 3+ atom, in agreement with experimental observations. The observed ferromagnetism should be a result of oxygen vacancies in VO 2 (M1) nanobelts.