Stability of Antiferroelectric and Ferroelectric Phases in Low Ti Concentration PbZr1-xTixO3

Abstract

The structural phase transitions of low Ti concentration 1 wt% Nb-doped PbZr1-xTixO3 (0.015\\leqslant x\\leqslant0.030) were studied by Raman scattering spectroscopy and dielectric measurement in the temperature range from -170°C to 300°C. The rhombohedral low-temperature ferroelectric FR(LT) phase, the rhombohedral high-temperature ferroelectric FR(HT) phase and the antiferroelectric orthorhombic AO phases are more distinguishable by Raman spectra in comparison to the spectra of antiferroelectric pure PbZrO3 and ferroelectric PZT where x=0.05, as reported previously. The phase boundary of antiferroelectric orthorhombic and ferroelectric rhombohedral phases exists at the Ti content of x=0.025, where the bistability of two phases is observed. At this critical composition, both phases appear separate with different temperature treatments. The Curie temperature decreases as x decreases. For x > 0.025, FR(LT) to FR(HT) transition temperature decreases as x decreases, and its thermal hysteresis is about a few degrees. For x < 0.025, AO to FR(HT) transition temperature increases as x decreases, and its thermal hysteresis is several tens degrees. Above Tc, the intense quasi-elastic scattering appears at x=0.03, it becomes weak as x decreases. This suggests that the origin of the quasi-elastic scattering might be that the nano-size polar clusters are induced by low concentrarion Ti ions.