Preparation and Characterization of Room-temperature Ferromagnetic Ni-doped TiO2 Nanobelts

Ni-doped anatase TiO2 nanobelts (NBs) with different Ni2+ contents were simply prepared by combining ion-exchange with hydrothermal treatment. They were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), and magnetic measurement techniques. The results showed that Ni2+ cations doped into the TiO2 lattice and no metallic nickel clusters or nanoparticles could be found. The magnetic results demonstrated that the prepared Ni-doped TiO2 samples had complex magnetic mechanism including room-temperature ferromagnetic and paramagnetic behaviors, and with the increase of Ni2+ content, the magnetization also increased under the same applied field owing to uniform distribution of Ni2+ ions in TiO2 nanobelts.