Synthesis, structural and magnetic properties of CeO2 nanoparticles

CeO₂ nanoparticles were prepared by a simple co-precipitation method and the structural and magnetic properties were studied. X-ray diffraction, Raman and selected area electron diffraction results indicate that the samples have the cubic fluorite structure without other impurity phases. Magnetisation measurements indicate that the CeO₂ nanoparticles calcined at different temperatures exhibit room temperature ferromagnetism (RTFM). The result of energy-dispersed X-ray spectrometry (EDS) analysis indicates that ferromagnetic impurities could not be responsible for the magnetic signals and that ferromagnetism (FM) is an inherent property of the material. It is found that the saturation magnetisation (M _s) of CeO₂ nanoparticles increases after annealing in reducing ambience and decreases after annealing in a rich-oxygen atmosphere, which confirms that the oxygen vacancies may play an important role in introducing FM.