Effect of Fe²⁺(Fe³⁺) Doping on Structural Properties οf CeO₂Nanocrystals

Abstract

We have measured the Raman scattering and magnetization of pure and Fe 2+ (Fe 3+ ) doped CeO2 nanopowders at room temperature. The Raman scattering spectra revealed the existence of CeO2 fluorite cubic structure for all investigated samples. The Raman active mode at about 600 cm −1 , seen in all samples, can be ascribed to the CeO2 intrinsic oxygen vacancies. Additional Raman modes at 720 cm −1 , 1320 cm −1 and 1600 cm −1 , which appear in the spectra of doped samples, can be assigned to maghemite (γ-Fe2O3) cation deficient structure, to 2ωLO IR-allowed overtone and two magnon structure, respectively. This implies that our powders are composed of mixed valence states and have defective structure. Presence of oxygen defect states and magnetic ions can be responsible for the observed ferromagnetism at room temperature in both pure and Fe doped samples.

Size and Surface Effects of Ce-Doped NiO and Co3O4 Nanostructures on Ferromagnetism Behavior Prepared by the Microwave Route

“…It is also emphasized that an increase of Ce dopant produces higher disorder in nickel and cobalt structure due to increased oxygen vacancy and metal interstitials which was already confirmed from the PL study. It was suggested that the existence of Ce 3+ –oxygen vacancy with Ni 2+ and Co 3+ ions contributed to the weak ferromagnetic behavior of NiO and Co 3 O 4 samples. − …”

Superparamagnetism in iron-doped CeO2−ynanocrystals

“…Starting materials were metal nitrates and sodium hydroxide. The details of the sample preparation procedure can be found in our recent publications [20,21]. The particle size of the samples under consideration, according to the x-ray diffraction (XRD) and Raman scattering measurements, was less than 5 nm [19].…”

Enhancing the dual magnetic and optical properties of co-doped cerium oxide nanostructures

“…The interactions between the spin moments of Ce 3+ and oxygen vacancy arise in accordance with F-centered exchange leading to the ferromagnetic character. 38,39 Saturation magnetization for EFCR (5.37 Â 10 À3 ) was found to be higher than that of pure CeO 2 (6.56 Â 10 À4 ). An increase in defect concentration has been observed on co-doping iron and europium as supported by our Raman spectra.…”