Infrared studies of the monoclinic-tetragonal phase transition in Pb(Zr,Ti)O3 ceramics

Recently, the observation of a new monoclinic phase in the PbZr1-xTixO3 (PZT) system in the vicinity of the morphotropic phase boundary was reported. Investigations of this new phase were reported using different techniques such as high-resolution synchrotron x-ray powder diffraction and Raman spectroscopy. In this work, the monoclinic → tetragonal phase transition in PbZr0.50Ti0.50O3 ceramics was studied using infrared spectroscopy between 1000 and 400 cm-1. The four possible ν1-stretching modes (Ti-O and Zr-O stretch) in the BO6 octahedron in the ABO3 structure of PZT in this region were monitored as a function of temperature. The lower-frequency mode ν1-(Zr-O) remains practically unaltered, while both intermediate ν1-(Ti-O) modes decrease linearly as temperature increases from 89 to 263 K. In contrast, the higher-frequency ν1-(Ti-O) and ν1-(Zr-O) modes present anomalous behaviour around 178 K. The singularity observed at this mode was associated with the monoclinic → tetragonal phase transition in PbZr0.50Ti0.50O3 ceramics