Neutron powder diffraction study of the phase transition in BaTi2O5

作者：Shigematsu Hirotake^*; Akishige Yukikuni; Gvasaliya Severian; Pomjakushin Vladimir; Lushnikov Sergey; Kojima Seiji

来源：Ferroelectrics, 2007, 346(1): 43-48.

DOI：10.1080/00150190601180190

• BaTi2O5
• crystal structure
• structural phase transition
• neutron powder diffraction

The structural phase transition and crystal structure of BaTi2O5 sol-gel powder have been studied by neutron powder diffraction. The crystal structure of BaTi2O5 at high-temperature phase has symmetry with the space group of C2/m from an extinction rule and a disappearance of spontaneous polarization. Lattice parameters are a = 17.0040(4)angstrom, b = 3.9455(1)angstrom, c = 9.5236(2)angstrom, beta = 102.941(2)degrees and V = 662.706(23)angstrom(3) at 900 K. There are two kinds of Ba (Ba1 and Ba2) and three kinds of TiO6 octahedra (Ti1O(6), Ti2O(6) and Ti3O(6)), and the unit cell has six BaTi2O5 molecules, Z = 6. All atoms are situated on the mirror planes with y coordinates of 0 of 1/2. The high-to-low temperature phase transition will be characterized by the atomic displacement of Ti and other oxygen atoms like a Slater mode, in Ti1O(6) octahedron.

• 出版日期2007