Monoclinic-tetragonal phase transition in Pb(Zr_1-xTi_x)O₃ studied by infrared spectroscopy

The discovery of a new monoclinic phase in the PbZr_1-xTi_xO₃ (PZT) system in the vicinity of the morphotropic phase boundary (MPB), previously considered as a region where the rhombohedral and tetragonal phases of PZT coexist, was recently reported. Investigations of this new phase were reported using different techniques such as high-resolution synchrotron x-ray powder diffraction and Raman spectroscopy. The main objective has been to define a new phase diagram of PZT. In this context, infrared spectroscopic studies were performed in the vicinity of the MPB and studies were initially centred on a PZT sample with x = 0.49 mol% Ti content. Results suggested that the monoclinic → tetragonal phase transition occurs at 237 K, confirming the use of IR as a useful technique to investigate this phase transition.