In this study, we examined the impact of iron doping on the structural, chemical, and magnetic properties of ceria (Ce1-xFexO2). Samples were produced in triplicate through a coprecipitation approach in a forced hydrolysis synthesis that yielded consistently sized nanocrystals using three different cerium precursors: cerium chloride, cerium ammonium nitrate, and cerium nitrate. Particles were characterized by x ray diffraction (XRD), x ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR) spectroscopy, and vibrating sample magnetometry (VSM). XPS and EPR data shows iron to be in the Fe3+ state and confirms the nominal dopant concentration. The moment per Fe ion found was largest at the lowest dopant concentrations, and quickly decreased as the concentration was increased. We used XPS to estimate the Ce3+/Ce4+ ratio and observed a linear relation between the saturation magnetization and the Ce3+/Ce4+ ratio.
Beausoleil, Geoffrey L. II; Thurber, Aaron; Rao, S. S.; Alanko, Gordon A.; Hanna, Charles; and Punnoose, Alex. (2012). "Concentration Dependence of Magnetic Moment in Ce1-xFexO2". Journal of Applied Physics, 111(7), 07B546-07B546-3. http://dx.doi.org/10.1063/1.3688933