Effect of structure distortion and oxygen vacancy on ferromagnetism in hydrothermally synthesized CeO2 with isovalent Zr4+ doping

Abstract

The influences of isovalent Zr4+ doping on structure and ferromagnetic property in hydrothermally prepared nanoscale CeO2 are investigated. Results suggest that Zr ions tend to incorporate into substitutional sites and then occupy interstitial sites or the surface at a critical doping concentration. The substituted incorporation of Zr4+ can significantly increase structure distortion and facilitate reduction of Ce4+ and production of oxygen vacancies (VO). With Zr doping, the saturation magnetization (MS) increases and then decreases, where the maximal MS appears at Ce0.94Zr0.06O2 sample. Air annealing Ce0.94Zr0.06O2 sample leads to the reduction of ferromagnetism. PL analyses reveal the emergent ferromagnetism may be closely related to structure distortion and VO defects induced by Zr on substitutional sites. The VO mediated F-center exchange mechanism can be used to interpret the RT ferromagnetic behavior in Zr-doped samples.