Charge-ordered domain structure in Yb Fe2 O4 observed by energy-filtered transmission electron microscopy

The charge-ordered domain structure of Yb Fe2 O4 has been studied by energy-filtered transmission electron microscopy. Dark-field imaging by using a spot of diffuse scattering revealed nanometer-sized charge-ordered domains. The domain size, which represents the approximate correlation length of the charge ordering, ranges from 3 to 7 nm within the c plane near room temperature, while the domain thickness along the c axis is smaller. Although the charge-ordered domains grow slightly upon cooling, the domain size is still within nanometers over the observed temperature range. The result demonstrates that the charge ordering cannot be developed in a long-range order due to significant frustration in the triangular lattice.