Microstructure-dependent magnetic anisotropy in nanorod vanadium oxide room-temperature ferromagnetic thin films using reactive sputtering

•Rod-like nanocrystals VOx thin films were prepared by magnetron sputtering.•The VOx film is a pure phase with a stoichiometric ratio between V2O3 and VO2.•The VOx film exhibits room-temperature ferromagnetic semiconductor behaviours.•The magnetic anisotropy of VOx films depends on the orientation of nanorods of the thin films. Vanadium oxides (VOx) with a strong correlated electronic effect have been widely used in the photoelectric field due to their metal–insulator transition characteristics. More attention should be paid to the magnetic properties of VOx thin films when developing spintronic devices. In this study, we prepare a nanorod VOx thin film on a sapphire Al2O3(0001) substrate by reactive sputtering. The results indicate that the prepared film exhibits room-temperature ferromagnetic semiconductor behaviors and is a mixed phase VOx film. The ferromagnetic source of the prepared film is well explained by the local electronic polaron model. In addition, magnetic anisotropy seems to depend on the orientation of nanorods of the thin film, which aids in the design of functional spintronic devices by controlling the microstructure to change the direction of the magnetic moment. Such findings will pave the way for the use of VOx films in spintronics.