Crystal structure and electron density distribution analyses of NdCeO for electrolyte by Rietveld/ maximum entropy method

Taguchi, Tomitsugu; Igawa, Naoki   ; Birumachi, Atsushi; Asaoka, Hidehito  ; Miwa, Shuhei  ; Osaka, Masahiko  

Rare-earth doped ceria exhibits both ionic and electronic conductions, and those ceria with higher ratio of ionic conduction against electronic conduction is used as a solid electrolyte for solid oxide fuel cells. The electron density distributions in crystals are closely related to the electron diffusing pathway which affects the electronic conduction. In this study, we investigated the electron density distribution of doped ceria as a function of the content of NdO-dopant to deduce the ratio of the electronic to ionic conduction. The crystal structure was refined with the space group, -3, which is the same as undoped ceria. Ce and Nd ions randomly occupied the 4 site and O ion the 8 site. The electron conduction pathway was distributed through the 4-8 and 8-8 sites. The relationship between crystal structural change and electron density distribution as a function of the content of NdO dopant will be discussed.