SciELO - Scientific Electronic Library Online

 
vol.5 issue1Ultrasonic Measurements In Brazilian HardwoodSusceptibility to Stress Corrosion Cracking of 254SMO SS author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Materials Research

Print version ISSN 1516-1439

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 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.

        · text in English     · pdf in English