Room-temperature ferromagnetism in Ti 1− x V x O 2 nanocrystals synthesized from an organic-free and water-soluble precursor
ABSTRACT Ti1−xVxO2 nanocrystals were prepared by employing a novel and water-soluble precursor via hydrothermal method, and the microstructure and magnetic properties have been investigated. All the samples belong to a pure anatase structure and exhibit room-temperature ferromagnetism (RTFM) without any trace of vanadium oxides or clusters. After V doping, the anatase structure is retained, while crystal growth is restrained. The homogenous distribution of V, in V4+ chemical state, in TiO2 lattice is confirmed by X-ray powder diffraction (XRD), energy-dispersive X-ray spectra (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses. Ferromagnetism in Ti1−xVxO2 is revealed to be highly dependent on the V content and defect concentrations. Furthermore, the annealing study in various atmospheres indicates that the oxygen vacancies and interstitials play a crucial role in inducing ferromagnetism in Ti1−xVxO2 system, and the origin of RTFM can be explained by bound magnetic polaron model.
- SourceAvailable from: Takeshi Morikawa[show abstract] [hide abstract]
ABSTRACT: To use solar irradiation or interior lighting efficiently, we sought a photocatalyst with high reactivity under visible light. Films and powders of TiO(2-x)N(x) have revealed an improvement over titanium dioxide (TiO2) under visible light (wavelength < 500 nanometers) in optical absorption and photocatalytic activity such as photodegradations of methylene blue and gaseous acetaldehyde and hydrophilicity of the film surface. Nitrogen doped into substitutional sites of TiO2 has proven to be indispensable for band-gap narrowing and photocatalytic activity, as assessed by first-principles calculations and x-ray photoemission spectroscopy.Science 08/2001; 293(5528):269-71. · 31.03 Impact Factor