Structural and electromechanical study of Bi0.5Na0.5TiO3-BaTiO3 solid-solutions

Abstract

Solid solution of (1-x)Bi0.5Na0.5TiO3-xBaTiO3 have been synthesized via conventional solid-state reaction route. Structural changes of the solid-solutions were investigated by using X-ray diffraction, Rietveld refinement Raman spectroscopy and piezoelectric studies. X-ray diffraction analysis shows a distinct 002/200 peak splitting appearing at x = 0.07 showing the coexistence of rhombohedral and tetragonal phase. Raman spectroscopy shows a splitting of (TO3) mode at x = 0.07 confirming the presence of the morphotropic phase boundary region. The dominant bands in the Raman spectra are analyzed by observing the changes in their respective peak positions, widths and intensities as the x increases. The piezoelectric properties of the solid solution increase with rise in BaTiO3 content and shows optimum value at x = 0.07 owing to the co-existence of two ferroelectric phases. Based on these results, it is suggested that the morphotropic phase boundary in the studied system lies in the composition x = 0.07.