Phase transitons with respect to temperature in La³⁺ and Ca²⁺ modified PbZrO₃

Antiferroelectric (AFE) materials show great promise for electrical energy storage applications. The energy stored (W_D) depends primarily on the switching field (E_s) and the induced polarisation (P). The AFE phase is smaller than the ferroelectric (FE) phase into which it transforms, which means that the AFE phase can be stabilised by minimising its volume by appropriate chemical modification, thus increasing E_s - PbZrO₃, modified with La³⁺, Ca²⁺ and Ti², was chosen for this study. The aim was to characterise the phase transitions in these systems with respect to temperature. This yielded phase diagrams for the families studied, complementing electric field investigations and providing greater understanding of the relative phase stabilities. Evidence of incommensurate phases was revealed at intermediate temperatures in all the families. The data analysis included Lorentz factor calculations, thus relating the observations to soft-mode theory.