Structure analysis of ferroelectric Bi4Ti3O12 by using X-ray powder diffraction

Abstract

The structure analysis of Bi4Ti3O12 was performed by using X-ray powder diffraction data to determine a suitable structure system. Two kinds of structural models, monoclinic (M-model) and orthorhombic (O-model), were assumed, and Rietveld refinement was carried out. The weighted and profile R-factors, R-wp and R-p, obtained from the refinement results based on the O-model were 19.54 and 14.84, respectively. On the basis of the M-model, both of the R.-factors, R-wp and Rp, decreased to 14.82 and 10.74, respectively. The goodness-of-fit indicator, S (= R-wp/R.(e)), also decreased from 1.43 to 1.09. The final lattice parameters calculated from the refinement results were a = 5.4496(l) Angstrom, b = 5.4105(l) Angstrom, and c = 32.8136(9) Angstrom. The beta angle was 89.96(3)degrees.