Concentration Dependence of Magnetic Moment in Ce_1-xFe_xO₂

Geoffrey L. Beausoleil II, Boise State University
Aaron Thurber, Boise State University
S. S. Rao, Boise State University
Gordon A. Alanko, Boise State University
Charles Hanna, Boise State University
Alex Punnoose, Boise State University

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Copyright 2012 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics 111(7) and may be found at: DOI: 10.1063/1.3688933.

Abstract

In this study, we examined the impact of iron doping on the structural, chemical, and magnetic properties of ceria (Ce_1-xFe_xO₂). 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.