Observation of antiphase domains in BiFeO₃ thin films by X-ray diffraction

Bismuth iron oxide, BiFeO₃ (BFO), thin films were grown on LaNiO₃-coated SrTiO₃ (0 0 1) substrates by chemical solution deposition method with different annealing ambiences of oxygen and nitrogen. Structural properties of the samples were investigated by X-ray diffraction and scanning electron microscopy, showing the BFO layers have a columnar structure and pseudo-tetragonal phase structure. Extinction of the first-order diffraction has been observed, which is due to the presence of antiphase domains in the BFO films. Nitrogen as the annealing ambience can increase the density of the antiphase domains (APD) in the films compared to oxygen. Electricity measurements show that the samples of nitrogen annealing ambience have less leakage current than those of oxygen. We suggest that the existence of the planar defects in the BFO films can decrease the leakage current.