Combined structural refinement of Bi 4Ti 3O 12 using X-ray and neutron powder diffraction data

Abstract

The combined structural refinement using X-ray and neutron powder diffraction data was carried out to determine the crystal system and to get the structural information of Bi 4Ti 3O 12. Of the two crystal systems, monoclinic and orthorhombic, the monoclinic system was more suitable than the orthorhombic one as a crystal system of Bi 4Ti 3O 12 at room temperature. The final weighted R-factor, R wp, on the all data was 7.02% ( R wp=15.03% and 4.97% for X-ray and neutron powder diffraction data, respectively) and the goodness-of-fit indicator, S (= R wp/ R e), was 1.16. The structural parameters of Bi 4Ti 3O 12, such as lattice parameters, atomic coordinates and isotropic thermal parameters, were successfully determined on the basis of the monoclinic crystal system. The lattice parameters obtained from the combined structural refinement were a=5.4483(1) Å, b=5.4092(1) Å and c=32.8111(4) Å. The remnant polarization ( P r) of Bi 4Ti 3O 12, 2 P r, showed 19.24 μC/cm 2.