On-line version ISSN 1980-5373
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 1980-5373. 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 Sr0.61Ba0.39Nb2O6, 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.