Microstructure, X-ray diffraction, dielectric and Raman spectroscopy studies of CaxSryBa1−(y+x)Nb2O6 ceramics

• We studied new ceramics compositions.
• Dielectric measurements have been confirmed by DSC.
• Raman Analysis confirms our dielectric results.

We have studied CaxSryBa1−(y+x)Nb2O6 (CSBN(x)) ceramics with tungsten-bronze structure. Ceramics were prepared with the conventional solid-state reaction for (x = 0.1, y = 0.1), (x = 0.1, y = 0.2) and (x = 0.2, y = 0.1). Phase purity, structure and crystallinity were investigated with X-ray diffraction showing pure phases with tetragonal symmetries. Microstructural analysis was performed using SEM. The microstructure of CSBN(x) ceramics showed a variation in grain shape and size. Dielectric measurements indicated the presence of ferroelectric-paraelectric phase transition at high temperatures which has been confirmed by DSC analyses. Polarizations versus electric field (P-E) loops were measured at different temperature. The Raman spectra of CSBN(x) as a function of temperature were also recorded in order to investigate the phase transformation. The vibrational spectra of CSBN(x) ceramics are dominated by broad and multi-component bands related to the internal vibrations of the NbO6 octahedral.

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