Effect of Iron Impurities on Magnetic Properties of Nanosized CeO2 and Ce-Based Compounds

CeO2 samples prepared by three technological procedures from the same cerium source, namely cerium (III) nitrate hexahydrate, are studied from the viewpoint of structure, chemical and phase composition, and micro- and macro-magnetic properties. The scanning and transmission electron microscopies completed by energy-dispersive X-ray (EDX) analysis yield nano-structural natures and homogenous chemical compositions of the ceria samples, confirmed also by X-ray diffraction. The diamagnetic, paramagnetic, and ferromagnetic phases in all samples follow from an analysis of the room- and low-temperature measurements of hysteresis loops. Iron impurities in ppm amounts are clearly detected by Fe-57 Mossbauer spectrometry not only in the ceria samples but also in the selected input chemicals used for their preparation. This contributes to the explanation of the magnetic behaviour of nanosized ceria.