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Several pellets of general formula Ba1-xMx(Ti1-xLix)O3-3xF3x were prepared from BaTiO3, MF2 ( M = Ca, Sr, Ba or Pb ) and LiF powders then sintered by the conventional solid state route at 900 or 1000°C for 1, 2 or 4 hours. X-Ray powder diffraction patterns were collected at room temperature and SEM observations were carried out. Dielectric measurements were performed between 150 and 450K in the frequency range 50Hz - 40MHz. All the ceramics exhibit a very broad ferroelectric displacive phase transition in the temperature range 255K ≤ TC ≤ 328K.The ε' r - T curves and the values of tanδ are compatible with the Z5U class of capacitors. Furthermore, a Debye dielectric relaxation occurs in these oxifluorids in the frequency range 4MHz ≤fr ≤ 38.5MHz.

A mixture of NaF and MgF 2 has been used to sinter SrTiO 3 at low temperature. A new solid solution Sr 1-x Na x (Ti 1-x Mg x )O 3-3x F 3x (0 ≤ x ≤ 0.20) has been obtained after sintering at 950 °C for 2 hours. From the X-ray diffraction analysis, each sample is a perovskite single phase with an orthorhombic symmetry whatever the value of x. Dielectric measurements have been performed as a function of temperature (300 K ≤ T ≤ 773 K) at two frequencies (100 Hz or 1000 Hz). DSC analysis have been carried out between room temperature and 873 K.Sr 1-x Na x (Ti 1-x Mg x )O 3-3x F 3x

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