Effect of doping in Ce1-xTMxO2 (TM = Mn, Cr, Co and Fe) nanoparticles obtained by hydrothermal method

The structural and magnetic properties of TM-doped CeO2 nanoparticles obtained by hydrothermal method are reported. X-ray diffraction (XRD), X-ray fluorescence (XRF), transmission electronic microscopy (TEM), UV/vis absorption and temperature, field-dependent magnetic measurements are used to study the samples. The Rietveld refinement analysis of XRD patterns show that nanoparticles have a cubic structure with average sizes ranging from 8 to 12 nm. TEM images reveal that nanoparticles have a spherical-like shape and a small particles size distribution. The UV/vis absorption data allow us to state that the band gap remain unaffected by the doping. The magnetic measurements indicate that the TM-doped samples exhibit a magnetic saturation at T = 5 K and paramagnetic behavior at T = 300 K. Besides, the number of paramagnetic ions, n, was evaluated for fitting the chi(T) curves to Curie-Weiss law. The obtained n values show to be TM- and concentration-dependent and smaller than the nominal concentration for all samples.