Study on superstructure in ion co-doped BiFeO 3 by using transmission electron microscopy

La 3+ and V 5+ co-doped BiFeO 3 ceramics are synthesized by rapid liquid sintering technique. The modulated structure in Bi 0.85 La 0.15 Fe 0.97 V 0.03 O 3 is investigated by using transmission electron microscopy (TEM). Two kinds of superstructures are observed in the samples. One is the component modulated superstructure and twin-domain, which is generated by La 3+ ordered substitution for Bi 3+ and frequently appears. The chemical composition of the superstructure is explored by x-ray energy dispersive spectroscopy (EDS). The model of the ordered structure is proposed. Simulation based on the model is conducted. The second is the fluorite-type δ -Bi 2 O 3 related superstructure. The relation between the ferroelectric property and the microstructure of the sample is also discussed.