Preparation of partially Y- or Yb-substituted SrFeO3- with cubic perovskite structure and its electrical conduction properties
Year: 2025
Type: article
Abstract: SrFeO 3- δ prepared in air exhibits a tetragonal or orthorhombic perovskite crystal structure with an ordered distribution of oxide-ion vacancies at room temperature. Changing the crystal structure to cubic perovskite with a random distribution of oxide-ion vacancies is expected to improve the hole or oxide-ion conductivity. In this study, the crystal structure of SrFeO 3- δ was altered by partially substituting Y or Yb at the Sr or Fe sites. X-ray diffraction and X-ray absorption spectroscopy revealed that Y partially substituted only at the Sr site, whereas Yb could substitute at both the Sr and Fe sites. Both substitutions resulted in a cubic perovskite structure. Mössbauer spectroscopy detected charge delocalization from the Y- or Yb-substitution in the cubic phase. The degree of delocalization was higher in the Sr-site-substituted specimen than in the Fe-site-substituted specimen. The cubic phases of Sr 1- x Y x FeO 3- δ , Sr 1- x Yb x FeO 3- δ , and SrFe 1- x Yb x O 3- δ exhibited a semiconducting temperature dependence devoid of phase transition effects. The lower electrical conductivity of SrFe 1- x Yb x O 3- δ compared with that of Sr 1- x Yb x FeO 3- δ corresponded to the lower delocalization degree observed by Mössbauer spectroscopy. Sr 0.9 Y 0.1 FeO 3- δ and Sr 0.9 Yb 0.1 FeO 3- δ exhibited electrical conductivity comparable with that of cubic SrFeO 2.75 above 420 °C without the structural phase transition influence, indicating their application potential, e.g., for gas separation and electrodes in solid oxide fuel cells.
Source: Solid State Ionics
Authors: Keina Nagai, Chihiro Kato, Ryutaro Maehara, Taizo Yoshino, Takayuki Sugimoto, Kosuke Shido, Takuya Hashimoto, Fumito Fujishiro, Eiki Niwa, Motoyuki Matsuo
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,560
Funders: Nihon University, University of Tokyo
Awards: G5816929381, G7362747025
OpenAlex ID: W7106234239