Effect of manganese (Mn) doping on the structural, dielectric, ferroelectric, and ferromagnetic properties of ceria (CeO2)

Abstract

The Ce1-xMnxO2 ceramics were prepared using a solid-state route, with Mn doping concentrations of (x = 0.00, 0.03, 0.08, 0.13, and 0.18). Examination of X-ray diffraction patterns confirms the effective insertion of Mn into the CeO2 lattice, resulting in discernible changes in oxygen vacancy concentration and lattice expansion. X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of Ce3+, Ce4+, Mn3+, and Mn2+ oxidation states. The Photoluminescence (PL) spectra reveal the existence of oxygen vacancies, as manifested by the appearance of peaks within the energy range spanning from 3.1 eV to 2.71 eV. Raman spectra reveal a symmetric vibration around 466.81 cm-1 in all samples. The surface morphology of the samples exhibited subtle changes in grain size upon the introduction of Mn into CeO2. The dielectric behavior, investigated across a range of frequencies with varying Mn doping concentrations, exhibits an increased dielectric constant in Mn-doped CeO2, particularly with a smaller dielectric loss at lower frequencies. The ferroelectric response revealed a maximum recoverable energy density of 0.56 mJ/cm2 with an efficiency of 47.86% for CeO2. The room temperature magnetic response of the samples improved as Mn concentration increased, which is well explained by the Bound Magnetic Polarons (BMPs) and exchange interactions model. Overall, the studies show the effect of structural, electrical, and magnetic properties after doping with Mn, opening avenues for diverse applications of these ceramics.