Abstract

CARRIO, J.G. et al. Structure Refinement of (Sr,Ba)Nb₂O₆ Ceramic Powder from Neutron and X-Rays Diffraction Data. Mat. Res. [online]. 2002, vol.5, n.1, pp. 57-62. ISSN 1516-1439.  http://dx.doi.org/10.1590/S1516-14392002000100010.

The structure of polycrystalline strontium barium niobate at room temperature was refined by the Rietveld method. Sintered ceramic samples were used to collect powder neutron and X-ray diffraction data. The ratio Sr/Ba » 64/36 was found from the initial batch composition Sr_0.61Ba_0.39Nb₂O₆, corroborating with the quantitative X-ray dispersive spectroscopy (EDS) measurements. The structure is tetragonal with cell parameters a, b = 12.4504(3) Å and c = 3.9325(1) Å and space group P4bm. It was not necessary to introduce any positional disorder for the oxygen atoms. Cation Nb⁺⁵ displacements not parallel to the c direction are presented, which can influence the behavior of the ferroelectric properties.

Keywords : strontium barium niobate; tungsten bronze structure; X-ray diffraction; neutron diffraction.