Raman spectroscopy of Pb(Zr1−xTix)O3graded ceramics around the morphotropic phase boundary

Abstract

Lead zirconate titanate ceramics Pb(Zr_1–x Ti _x )O₃ with spatially graded composition from X = 46 to 49 were studied by Raman scanning microscopy and the results were compared with Raman spectra in PZT ceramics of different compositions around the morphotropic phase boundary (MPB). An E-symmetry mode located near 200 cm⁻¹ was found to be a measure of the tetragonality of PZT in both standard graded ceramics. The singular value decomposition method was applied to decompose the experimental spectra of the graded ceramics. Two main contributions were found: one is related to the intensity of the main transverse modes – especially the E(TO2) mode – and it gives evidence of the change between tetragonal and rhombohedral symmetries in the sample; the second one shows changes just through the spatial MPB and it is related to the intensities of A₁(TO2) and E(LO2) modes. All the phonons involved in the main changes correspond to Zr and Ti vibrations.