抄録
High-temperature phase transition of lanthanum aluminum titanate La0.68(Ti0.95,Al0.05)O3 has been studied using neutron powder diffraction and Rietveld method. The material is orthorhombic with space group Cmmm between 25 and 286C, while it is tetragonal with space group P4/mmm between 388 and 592C. The anti-phase tilt angle along b axis of the oxygen octahedron around Ti and Al atoms was found to induce the tetragonal-to-orthorhombic phase transition. The axial b/a ratio decreases with an increase of temperature and becomes unity at the transition temperature between 286 and 388C.
