LAUSR

Tungsten-doped TiO2 nano-composite powders were synthesized by a facile decomposition of a mixture of titanium tetrachloride (TiCl4) and sodium tungstate dihydrate (Na2WO4.2H2O). The X-ray diffraction method was utilized to study the crystal structures of the produced samples and analyzed with Rietveld refinement technique. The results confirmed forming a mixture of anatase [A] and brookite [B] for pristine TiO2 sample, which transformed into rutile [R] + brookite [B] with W-doping. The diffuse reflection spectroscopy (DRS) technique was used to study the optical properties and band gaps of the samples. The redshift of the band gap by W ion inclusion and blueshift with the hydrogenation were measured and discussed. It was concluded that the hydrogenation induced phase transformation from [A] to [R]. It was noticed a crucial role for the hydrogenation in the creation of room-temperature ferromagnetic (RT-FM) properties in host W-doped TiO2. This was explained by the generation of oxygen (O) vacancies as a vital condition for the creation of RT-FM. The magnetic measurements showed that hydrogenated rutile/brookite TiO2 nanopowder doped with 2.5 wt% W could create a magnetic saturation of ~ 15 memu/g. The obtained results are significant to the dilute magnetic semiconductor fabrication.