Crystal structure analysis of manganese and gallium doped hexagonal BaTiO3 by synchrotron radiation powder diffraction

Crystal structures of manganese doped and gallium doped metastable hexagonal barium titanate were investigated by high energy synchrotron radiation powder diffraction at BL02B2 in SPring-8. The Rietveld analyses reveal that the lattice of gallium doped sample is expanded along the c-axis, while the lattice is not changed in the manganese doped sample, although the ionic radius of gallium is almost same as that of titanium, and besides, that of manganese is fairly smaller. These results imply that the lattice is essentially expanding by the doping. It is considered that the lattice expanding is significant in the stabilization of the hexagonal phase.