Stability of antiferroelectric and ferroelectric phases in low Ti concentration PbZr1-xTixO3

The structural phase transitions of low Ti concentration 1 wt% Nb-doped PbZr1-xTixO3 (0.015 less than or equal to x less than or equal to 0.030) were studied by Raman scattering spectroscopy and dielectric measurement in the temperature range from -170 degrees C to 300 degrees C. The rhombohedral low-temperature ferroelectric F-R(LT) phase, the rhombohedral high-temperature ferroelectric F-R(HT) phase and the antiferroelectric orthorhombic A(O) 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. Ar this critical composition, both phases appeal separate with different temperature treatments. The Curie temperature decreases as x decreases. For x > 0.025, F-R(LT) to F-R(HT) transition temperature decreases as x decreases, and its thermal hysteresis is about a few degrees. For x < 0.025; A(O) to F-R(HT) transition temperature increases as x decreases, and its thermal hysteresis is several tens degrees. Above T-c, 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 concentration Ti ions.