Order-disorder at Fe-sites in SrFe2/3B´´1/3O3 (B´´ = Mo, W, Te, U) tetragonal double-perovskites

M. DEL C. VIOLA; M. S. AUGSBURGER; R. M. PINACCA; J. C. PEDREGOSA; R. E. CARBONIO; R. C. MERCADER

Elsevier

Año: 2003 vol. 175 p. 252 - 252

p style="TEXT-ALIGN: justify; LINE-HEIGHT: 200%; MARGIN: 0cm 0cm 0pt; TEXT-AUTOSPACE: ; mso-layout-grid-align: none" class="MsoNormal">We have prepared SrFe2/3B’’1/3O3 (B’’= Mo; U, Te, and W) double perovskites in polycrystalline form by ceramic methods. Phases with B’’=U; Te and W have been studied by X-ray powder diffraction and the results have been compared with neutron diffraction data available for B’’=Mo. At room temperature, the stoichiometric samples crystallize in the tetragonal crystal system (space group I4=m; Z = 4). Cell parameters when B’’=U; Te and W are a = 5.6936(1) Å, c = 8.0637(1) Å; a = 5.5776(1) Å, c = 7.9144(3) Å and a = 5.5707(3) Å, c = 7.9081(5) Å, respectively. The Mössbauer spectra at room temperature for all compounds show hyperfine parameters belonging