Multiple dielectric anomalies in xBiLaO3-(1-x)PbTiO3 piezoelectrics

Compositions of xBiLaO(3)-(1-x) PbTiO3 over the range 0 <= x <= 0.225 were calcined and sintered. The dielectric constant with temperature and differential scanning calorimetry measurements were in excellent agreement with respect to Curie-like tetragonal to cubic transformations starting at 495 degrees C for pure PbTiO3, shifting to lower temperatures with increasing x. For compositions of x >= 0.05, a second higher-temperature (similar to 600 degrees C) endotherm, and matching dielectric anomaly, were consistently observed, for which there were no structural changes indicated by hot-stage x-ray diffraction. This transformation was speculated to be based on a thermally induced desegregation of B-site cations.