Morphotropic Phase boundary in BNT-BZT solid solution: A study by Raman spectroscopy and electromechanical parameters

摘要

Lead-free perovskite ferroelectric ceramics of (1-x)(Bi0.5Na0.5)TiO3-x Ba(Zr0.25Ti0.75)O-3 [abbreviated as (1-x) BNT-xBZT] have been synthesized via conventional solid-state reaction route. Structural changes of the solid-solutions were investigated by using rietveld refinement of X-ray diffraction (XRD) data and Raman spectroscopy over the composition range 0 <= x <= 0.08. The unique phase transition behaviours are discussed in relation to the growth of Ba2+TiO3 and Zr4+TiO3 clusters upon the substitution of Ba2+ for (Bi0.5Na0.5)(2+) cations and Zr4+ for Ti4+ in the (1-x) BNT-xBZT solid-solutions. The splitting of (111) and (200) plane represents the presence of morphotropic phase boundary within the solid solution at x = 0.05. Raman spectroscopy exhibited a splitting of the (TO3) mode at x = 0.05 and confirmed the presence of MPB region. The piezoelectric properties of the solid solution increase with rise in Ba(Zr0.25Ti0.75)O-3 content and shows optimum value at x = 0.05 owing to the coexistence 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 = 0.05.