Influence of cerium dopant on magnetic and dielectric properties of ZnO nanoparticles

Ce-doped ZnO nanoparticles (NPs) with different Ce doping concentrations (0, 0.96, 1.96, 2.52 and 3.12 at.% of Ce) were prepared by the chemical co-precipitation method. Energy-dispersive analysis of X-rays confirms the presence of Ce in Ce-doped ZnO nanoparticles. Raman spectra revealed the hexagonal wurtzite structure of pure and Ce-doped ZnO nanoparticles and presence of various defects. The photoluminescence spectra exhibited enhanced violet and blue emission peak intensities for 0.96 at.% of Ce, while broad band green emissions decreased with Ce content. Electron paramagnetic resonance (EPR) studies revealed the presence of oxygen vacancies (V (O)), zinc vacancies (V (Zn)) and Ce3+ ions in the prepared ZnO nanoparticles. VSM studies showed room temperature ferromagnetism (RTFM) in the Ce-doped ZnO NPs. The substituted Ce(3+)ions found to induce RTFM along with V (O), V (Zn) in correlation with the results obtained from the EPR, PL and Raman studies. The variation of dielectric constants (epsilon (r)), dielectric loss (epsilon aEuro(3)) and ac conductivity (sigma (ac)) as a function of frequency and Ce concentration is studied using 'Maxwell-Wagner Model.'.