Dielectric response of ceramic Sr2−xBixTi2−xFexO6 (0≤x≤1.5) perovskites
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en
Article de revue
Ce document a été publié dans
Journal of Physics and Chemistry of Solids. 2015, vol. 81, p. 40-49
Elsevier
Résumé en anglais
Polycrystalline Sr2−xBixTi2−xFexO6 (x=0, 0.5, 1 and 1.5) perovskites have been synthesized by the ceramic method. Structural characterization from X-ray diffraction data showed that the symmetry evolves from centrosymmetric ...Lire la suite >
Polycrystalline Sr2−xBixTi2−xFexO6 (x=0, 0.5, 1 and 1.5) perovskites have been synthesized by the ceramic method. Structural characterization from X-ray diffraction data showed that the symmetry evolves from centrosymmetric cubic (Pm View the MathML source3¯m) to non centrosymmetyric rhombohedral (R3c) as iron and bismuth content increase. For the intermediate composition, x=1, a mixed phase is obtained, which mean symmetry matches the best with the orthorhombic one (Pbnm). EDS analyses showed that the effective compositions differ from the nominal ones, and they were confirmed from Rietveld refinements of XRD data. HRTEM experiments indicated that in the case of x=1.5, a superstructure along [001]c and [111]c is observed. The dielectric response is modified depending on the composition range x. The x=0 compound shows a Debye type relaxation implying oxygen vacancy cluster, whereas a relaxor ferroelectric behavior is obtained for the x=0.5 and x=1 samples. Finally, in the case of x=1.5, the dielectric behaviour is characterized by strong dependence of permittivity with temperature.< Réduire
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