Study of the morphotropic phase boundary in the lead-free Na<sub>1/2</sub>Bi<sub>1/2</sub>TiO<sub>3</sub>-BaTiO<sub>3</sub> system by Raman spectroscopy

Lead-free piezoelectric (100-x)Na1/2Bi1/2TiO3-xBaTiO3 solid solution ceramics are investigated by Raman spectroscopy and X-ray diffraction over a composition range of 0 ≤ x ≤ 10. Distinct changes in the Raman spectra and X-ray diffraction patterns were discussed in the light of a rhombohedral to tetragonal phase transition. The dominant bands in the Raman spectra were analyzed by observing the changes in their respective peak positions, widths and intensities as the composition increased. Based on these results, it is suggested that the morphotropic phase boundary in the studied system lies at the composition of x ≈ 5.5. This is further evidenced by the X-ray diffraction analysis.