%0 Journal Article
%A Mather, Glenn
%A Figueiredo, Filipe
%A Romero de Paz, Julio
%A García Martín, Susana
%T Strontium Superstoichiometry and Defect Structure of SrCeO3 Perovskite
%D 2008
%@ 0020-1669
%U https://hdl.handle.net/20.500.14352/96334
%X Strontium cerate (SrCeO3) is the parent phase of a family of prototype proton-conducting perovskites with important potential applications as electrolytes in protonic ceramic fuel cells, hydrogen-separation membranes, and sensors for hydrogen and humidity. Apparent nonstoichiometric behavior and the microstructure of SrCeO3 have been investigated. Phase analysis by X-ray diffraction indicates that single-phase material in the system Sr1+xCeO3+d is obtained for compositions x = 0.02-0.03 and that nominally stoichiometric SrCeO3 (x= 0) synthesized by either solid-state reaction or the citrate method is Sr-rich. Selected area electron diffraction confirms that the system crystallizes with the GdFeO3-type orthorhombic perovskite structure (space group Pnma). Structural defects characterized by high-resolution transmission electron microscopy include twin domain boundaries and SrO-rich, Ruddlesden-Popper-type planar defects. Magnetic susceptibility measurements down to 2 K indicate that the Ce3+ content is minor (0.01 mol per formula unit for slow-cooled material) and does not influence the observed nonstoichiometry.
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