Structural, optical and magnetic properties of cobalt doped hematite nanoparticles

Pure α-Fe₂O₃ and Co-doped α-Fe₂O₃ (CFO) nanoparticles were synthesized by Co-precipitation method. The structure and the morphology of the samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-visible diffuse reflectance spectroscopy (DRS), and a vibrating sample magnetometer (VSM). The results showed that CFO nanoparticles have rhombohedral structure and that the Co²⁺ ions were well incorporated into the α-Fe₂O₃ crystal lattice, which are consistent with the results obtained from Raman spectroscopy. The crystallite sizes were in the range 36-38 nm, which are consistent with the results obtained from TEM and SEM images. Meanwhile, the Co doping could extend the visible light absorption of α-Fe₂O₃ nanoparticles. Furthermore, magnetic investigations demonstrate that magnetic properties strongly depend on doping content.