Effect of magnetic element doping on the electronic and magnetic properties of CeO2 nano-particles

• Main Authors: Wei-Cheng Wang, 王偉丞
• Other Authors: Ching-Lin Chan
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/22659021649628159037

博士 === 淡江大學 === 物理學系博士班 === 102 === This study reports the electronic structure of magnetic element doped CeO2 nanoparticles (NPs). Systematic synchrotron radiation based X-ray spectroscopy analysis was utilized to investigate the electronic structures in CeO2 NPs, which is determined by coupled X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES). The result revealed that the magnetic properties are correlated to the electronic structures. Ce L3-edge and M4,5-edge spectra reveal the variations of the charge states of Ce. Transition metal (TM) K-edge and L2,3-edge spectra indicate the variations of their valence states upon TM doping. The pre-edge features of oxygen K-edge spectra due to the hybridization between cerium 4f and oxygen 2p states depend strongly on the concentration of magnetic element doping. Our results indicate that, for Fe-doped samples, ferromagnetic Fe3+-Vo-Ce3+ configuration is formed at low Fe concentrations (below 5%). While, at higher Fe concentrations, anti-ferromagnetic Fe3+-Vo-Fe3+ configuration is formed. For Cr-doped samples, the major effect of magnetic properties in Cr3+ doping system is formed the ferromagnetic Cr3+-Vo-Ce3+ configuration.