Structural evolution of bismuth sodium titanate induced by a-site non-stoichiometry: Neutron powder diffraction studies

作者：Jeong I K^*; Sung Y S; Song T K; Kim M H; Llobet A

来源：Journal of the Korean Physical Society, 2015, 67(9): 1583-1587.

DOI：10.3938/jkps.67.1583

• Bismuth Sodium Titanate
• Non-stoichiometry
• Neutron Powder Diffraction
• Octahedral Tilting

We performed neutron powder diffraction measurements on (Bi0.5Na0.5+x )TiO3 and (Bi0.5+y Na-0.5)TiO3 to study the structural evolution induced by the non-stoichiometry. Despite the nonstoichiometry, the local structure (r a parts per thousand currency sign 3.5 ) from the pair distribution function analysis is barely affected by a sodium deficit of up to -5 mol%. With increasing pair distance, however, the atomic pair correlations weaken due to the disorder caused by the sodium deficiency. Although the sodium and the bismuth share the same crystallographic site, their non-stoichiometries have rather opposite effects as revealed from distinctive distortions of the Bragg peaks. In addition, a Rietveld refinement demonstrates that the octahedral tilting is continually suppressed for sodium deficits up to -5 mol%. This is contrary to the effect of the bismuth deficiency, which induces little variation in the octahedral tilting.

• 出版日期2015-11
• 单位Los Alamos