Ferromagnetism in rare earth doped cerium oxide bulk samples

Magnetic properties of rare earth (RE) doped ceria (RE = Nd, Sm, Gd, Tb, Er and Dy) samples have been investigated and reported in this paper. Room temperature ferromagnetism (FM) was observed in calcined powders as well as in sintered samples of Nd and Sm doped CeO2, whereas other RE dopants (Gd, Tb, Er and Dy) in CeO2 exhibit paramagnetic behaviour. The origin of magnetism in these samples can be related to oxygen vacancies and formation of fluorite crystal structure. Though the magnetization was found to be lower as compared to transition metal (TM) doped ceria, the segregation of metallic and secondary phases can be avoided in RE doped CeO2. CeO2 doped with Sm ions in different concentration (1, 5 and 15%) were also studied to see the dopant effects on magnetic properties. The origin of magnetism in these samples may be related to the oxygen vacancies created due to RE dopants, which was confirmed from the peak around 555 cm−1 in Raman spectra.