Local structure study of phase transition behavior in Ba(Ti,Sn)O3 perovskite by X-ray absorption fine structure

In this work, BaTi1−xSnxO3 (BST) powders (x=0-0.95) were synthesized by a conventional mixed-oxide method. The phase information was investigated by a combination of X-ray diffraction and X-ray absorption spectroscopy techniques. The XRD measurements indicated the global phase transition from tetragonal to cubic perovskite structure. From the synchrotron X-ray Absorption Near-Edge Structure (XANES) measurements at the Ti K-edge and Sn L3-edge, it was seen that an increase of Sn content in BaTiO3 affected the phase transition behavior and local structure of BST. In addition, the local structure of Ba(Ti,Sn)O3 materials were experimentally determined and compared with that obtained from the simulation. The local structure obtained from the XANES technique provided additional structural information unavailable from XRD investigation. Finally, the phase transition behavior from relaxor ferroelectric to polar cluster in BST system was discussed and attributed mainly to the change in the local structure.