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en
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Ce document a été publié dans
Central European Journal of Chemistry. 2009, vol. 7, n° 2, p. 159-163
Springer Verlag
Résumé en anglais
Various compositions (1-x)BaTiO<sub>3</sub> + xPbF2+ xLiF were prepared, shaped to pellets then sintered at 900°C for 2 h in gold sealed tubes. The purity and the symmetry of the obtained samples were checked by X-ray ...Lire la suite >
Various compositions (1-x)BaTiO<sub>3</sub> + xPbF2+ xLiF were prepared, shaped to pellets then sintered at 900°C for 2 h in gold sealed tubes. The purity and the symmetry of the obtained samples were checked by X-ray diffraction. A new solid solution with Ba<sub>1-x</sub> Pb<sub>x</sub>(Ti<sub>1-x</sub>Li<sub>x</sub>) O<sub>3-3x</sub> F<sub>3x</sub> formula occurs in the composition range 0 ≥ x ≥ 0.20. SEM observations were performed on polished and fractured ceramics. The complex permittivity was measured as a function of temperature (-120°C ≥ T ≥ 250°C) and frequency (50 Hz ≥ f ≥ 4 × 10<sup>7</sup> Hz). The dielectric performances are the best for ceramic Ba<sub>0.97</sub>Pb<sub>0.03</sub>(Ti<sub>0.97</sub> Li<sub>0.03</sub>)O<sub>2.91</sub>F<sub>0.09</sub>. The real component ε'<sub>r</sub>, exhibits a maximum of approximately 7500 at the ferroelectric Curie temperature T<sub>C</sub> ≈ -18°C, the dielectric losses tan δ value being 0.012. At room temperature, the relaxation frequency f<sub>r</sub> is around 40 MHz for this ceramic. This novel ferroelectric oxifluoride is a promising material for applications, in particular in the field of Z5U multilayer capacitors.< Réduire
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