Effect of Pb^(2+) substitution on the quantum paraelectric behaviour of CaTiO_(3)

Abstract

Results of low temperature dielectric measurements on the mixed (Ca_(1-x)Pb_(x))TiO_(3) system are presented to show that a dielectric anomaly appears for x \geq 0.10. The observed dielectric peak is shown to be due to a thermodynamic phase transition and not due to a relaxor or dipole glass type transition. Curie-Weiss fit to the dielectric constant gives negative Curie temperature which points towards an antiferroelectric transition. Arguments are advanced to propose that CaTiO3 may be an incipient antiferroelectric in which Pb^(2+) substitution stabilises the antiferroelectric phase.