The particle size-dependent optical band gap and magnetic properties of Fe-doped CeO2 nanoparticles

Fe-doped CeO₂ (0%-0.08%) nanoparticles have been synthesized by chemical precipitation method. The nanoparticles have been investigated using thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscope (TEM), UV-Vis spectrometer and Vibrating sample magnetometer (VSM) techniques. XRD data exhibited the cubic zincblende type structure for Fe-doped CeO₂ nanoparticles. The size of nanoparticles was found to decrease from 20 nm (0%) to 14 nm (8%) with increasing Fe concentration which is confirmed by TEM micrographs. The optical absorption spectra of the nanoparticles show the blue-shift of the wavelength of absorption maximum from 550.2 nm to 336.4 nm with increasing Fe concentration owing to decreasing in particle size. The energy band gap was found to increase slightly with increasing the Fe doping level which was attributed to the decrease in the particle size with Fe content originated from quantum confinement effect. The doped Fe-doped CeO₂ nanoparticles revealed room temperature ferromagnetism.