Structural and dielectric properties of Na1−xBaxNb1−x(Sn0.5Ti0.5)xO3 ceramics
Résumé
Lead-free (1 − x)NaNbO3/xBa(Ti0.5Sn0.5)O3 (x = 0.1, 0.125, 0.15, 0.175, 0.2, and 0.3) ceramics were elaborated by the conventional ceramic technique. Sintering has been made at 1523 K for 2 h. The crystal structure was investigated by X-ray diffraction with CuKα radiation at room temperature. As a function of composition, these compounds crystallize with tetragonal or cubic symmetry. Dielectric measurements show that the materials have a classical ferroelectric behavior for compositions in the range 0.10 ≤ x ≤ 0.15 and relaxor one for compositions in the range 0.15 < x ≤ 0.30. Temperatures T C or T m decrease as x content increases. The ferroelectric behavior has been confirmed by hysteresis characterization. For x = 0.1, a piezoelectric coefficient d 31 of 42.146 pC N−1 was obtained at room temperature. The evolution of the Raman spectra was studied as a function of temperature for x = 0.1.