Studies on structural, dielectric and optical properties of (Ba(0.95)Ca(0.05))(1−x)(Ti(0.8)Sn(0.2))(1−x)Na(x)Nb(x)O(3) lead-free ceramics

(Ba(0.95)Ca(0.05))(1−x)(Ti(0.8)Sn(0.2))(1−x)Na(x)Nb(x)O(3) (BCNTSNO(3)) lead-free ceramics with compositions (x = 0.75, 0.8 and 0.85) were synthesized through the traditional solid-state reaction method. X-ray powder diffraction analysis showed the formation of a single phase compound crystallized in tetragonal space group P4mm. The evolution of Raman spectra displayed a disorder introduced into the structure, which favors a ferroelectric relaxor behavior. The dependence of the dielectric properties on temperature exhibited two composition ranges with different behaviors. Ferroelectric relaxor properties were observed for the compositions x < 0.85 and the classical ferroelectric behavior for x = 0.85. Lead free (Ba(0.95)Ca(0.05))(1−x)(Ti(0.8)Sn(0.2))(1−x)Na(x)Nb(x)O(3) ceramics exhibited larger dielectric constants than those of parent crystal NaNbO(3), suggesting that it is a good candidate for lead-free ceramics in several industrial applications. Using UV-Vis spectroscopy, the optical band gap energy of ceramics (Ba(0.95)Ca(0.05))(1−x) (Ti(0.8)Sn(0.2))(1−x)Na(x)Nb(x)O(3) is found at 2.89, 2.92, and 3.05 eV for x = 0.75, 0.8 and 0.85, respectively.