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

We investigated the structure and magnetic properties of Ce-doped NiO and Co3O4 samples. The multiemission centers created in the nanostructures observed from PL spectra were obviously due to the formation of interstitials (Nii and Coi) and oxygen vacancies (VO) by the incorporation of Ce3+ ions into the lattice site which affects the band gap structure of the material. Room-temperature magnetic study was demonstrated for Ce-doped NiO and Co3O4 nanostructures using a vibrating sample magnetometer. The origin of magnetism in these samples was related to the finite size and importantly oxygen vacancies created by the Ce ion dopant, which was confirmed from the decrease of magnetization value at room temperature compared to undoped NiO and Co3O4 samples.