Reconstructed stacking faults in cobalt-doped hexagonal LuFeO3 revealed by mapping of cation distribution at the atomic scale

The structure of an epitaxial thin film of cobalt-doped hexagonal LuFeO3 was studied by aberration-corrected high-resolution scanning transmission electron microscopy. The distribution maps of the chemical elements in the film were obtained using atomically resolved energy-dispersive X-ray spectroscopy. The study showed that cobalt ions have a strong tendency towards forming double layers of (Fe/Co)O-2.5 between the Lu-O layers in a hexagonal structure. A significantly smaller amount of cobalt is found in single layers of FeO1.5, suggesting the presence of a trigonal-bipyramidal coordination of cobalt. The hexagonal LuFeO3 structure contains numerous reconstructed stacking faults that represent intergrown structural fragments of LuFe2 - xCoxO4. Magnetization measurements revealed a decrease in the magnetic transition temperature of the LuFe0.7Co0.3O3 thin film compared to those of the parent hexagonal LuFeO3 and LuFe2 - xCoxO4 forms.