Combined structural refinement of Bi4Ti3O12 using X-ray and neutron powder diffraction data

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 Bi4Ti3O12. Of the two crystal systems, monoclinic and orthorhombic, the monoclinic system was more suitable than the orthorhombic one as a crystal system of Bi4Ti3O12 at room temperature. The final weighted R-factor, Rwp, on the all data was 7.02% (Rwp=15.03% and 4.97% for X-ray and neutron powder diffraction data, respectively) and the goodness-of-fit indicator, S (=Rwp/Re), was 1.16. The structural parameters of Bi4Ti3O12, 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) A˚, b=5.4092(1) A˚ and c=32.8111(4) A˚. The remnant polarization (Pr) of Bi4Ti3O12, 2Pr, showed 19.24 μC/cm2. [Copyright &y& Elsevier]