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

TL;DR

This study investigates how substituting Pb^(2+) into CaTiO_(3) affects its dielectric properties, revealing a thermodynamic phase transition indicative of incipient antiferroelectric behavior stabilized by Pb^(2+) doping.

Contribution

It demonstrates that Pb^(2+) substitution induces a thermodynamic phase transition in CaTiO_(3), suggesting the material is an incipient antiferroelectric stabilized by doping.

Findings

Dielectric anomaly appears for x ≥ 0.10

Transition is thermodynamic, not relaxor or dipole glass

Negative Curie temperature indicates antiferroelectric behavior

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.