Vacancy Ordering in γ-Fe₂O₃: Synchrotron X-ray Powder Diffraction and High-Resolution Electron Microscopy Studies

Abstract

This paper reports synchrotron X-ray powder diffraction and high-resolution electron microscopy studies of the structural arrangement in γ-Fe2O3. Powder diffraction data as well as high-resolution electron microscopy show that the basic structure of γ-ferric oxide possesses cubic symmetry (space group P4332), whereas the ordered distribution of the cation vacancies on the octahedral positions results in the formation of the tetragonal superlattice (space group P41212). The character of the superstructure orientation with respect to the developed planes of the γ-Fe2O3 microcrystals obtained by different preparative techniques is also discussed.