Room temperature ferromagnetism of iron-doped rutile TiO2 nanorods synthesized by a low temperature method

Nanorods of Fe-TiO2 were synthesized at 100 °C and room pressure by mixing titanium oxide wet gel TiO2·xH2O with a boiling solution of iron nitrate. The results of EDAX, performed on different selected area of the sample, revealed a homogeneous composition of about 3 at% Fe. Electron diffraction and XRD measurements show that the as-prepared Fe-TiO2 and annealed one at 550 °C have both a single rutile structure with no indication about the presence of a secondary phase. The transmission electron microscopy (TEM) micrographs show that both as-prepared Fe-TiO2 and annealed one at 550 °C have nanorod-shape with dimensions length by diameter of about 60 × 5 nm and 52 × 12 nm, respectively. Magnetization measurements show that both samples present a nonzero remanence and a coercivity of 108 and 120 Oe, respectively. At higher temperature, 850 °C, Fe-TiO2 decomposes to rutile TiO2 and new iron-titanate phase.