X-ray photoelectron spectroscopy and low temperature Mössbauer study of Ce³⁺ substituted MnFe₂O₄

Spinel Mn²⁺ Fe_2−x³⁺Ce_x³⁺O₄ (where x = 0.01–0.05) polycrystalline nanoparticles were fabricated by solution combustion method using glucose and urea as fuels. X-ray diffractogram (XRD) proved the witness of the cubic crystal consort of products which have the crystallite sizes in between 12 and 8 nm. The size of the sample was accomplished via transmission electron microscopy. The elemental composition of iron and manganese ions valences of MnCe_xFe_2−xO₄ samples were analyzed by X-ray photoelectron spectroscopy. XPS data reveals iron in all samples was trivalent; manganese was divalent, although tetravalent manganese ions were present on the surface of particles. Magnetic characterization of samples was done via Mössbauer spectroscopy at room temperature and at low temperatures (15 K). The Mössbauer analysis determines the consequence of Ce³⁺ substitution on isomer shift and quadrupole splitting of all samples. The low temperature Mössbauer spectroscopy results indicate that the presence of Ce³⁺ ions in the octahedron sites causes the decrease in the concentration of Fe³⁺ ions.