Additional phase transition in a PbZr0.87Ti0.13O3 single crystal

PbZr1-xTixO3 (PZT) ceramics are one of the most known and widely used piezoelectric materials. In order to understand the origin of the high piezoelectricity it is essential to also understand its phase diagram. Many recent papers have reported the modification of PZT phase diagram based on ceramic experimental data. This is due to difficulties to get good quality single crystal samples. We have succeeded in getting a good quality single crystal with x = 0.13. Based on temperature changes of elastic properties we confirmed the existence of additional phase transition appearing in the PbZr0.87Ti0.13O3. The temperature dependence of the elastic properties was investigated by means of piezoelectric measurements and Brillouin light scattering. We discussed the correlation between anomalies of the elastic properties found in these measurements, and suggested that, except for the two well-known phase transitions, these anomalies point to another phase transition below T-c. The structure and symmetry of this crystal have been tested with use of the x-ray diffraction at the room temperature.