Predicting morphotropic phase boundary locations and transition temperatures in Pb- and Bi-based perovskite solid solutions from crystal chemical data and first-principles calculations

TL;DR

This study demonstrates that the morphotropic phase boundary locations and transition temperatures in Pb- and Bi-based perovskite solid solutions can be accurately predicted using crystal chemical data and first-principles calculations, aiding materials design.

Contribution

The paper introduces a quantitative method to predict MPB positions and transition temperatures from ionic properties and first-principles data, advancing ferroelectric materials modeling.

Findings

MPB position depends linearly on ionic size and B-cation displacements.

Transition temperatures at MPB can be accurately predicted.

Structure-property correlations enable predictions for unsynthesized solutions.

Abstract

Using data obtained from first-principles calculations, we show that the position of the morphotropic phase boundary (MPB) and transition temperature at MPB in ferroelectric perovskite solutions can be predicted with quantitative accuracy from the properties of the constituent cations. We find that the mole fraction of PbTiO$_3$ at MPB in Pb(B$'$B$''$)O$_3$-PbTiO$_3$, BiBO$_3$-PbTiO$_3$ and Bi(B$'$B$''$)O$_3$-PbTiO$_3$ exhibits a linear dependence on the ionic size (tolerance factor) and the ionic displacements of the B-cations as found by density functional theory calculations. This dependence is due to competition between the local repulsion and A-cation displacement alignment interactions. Inclusion of first-principles displacement data also allows accurate prediction of transiton temperatures at the MPB. The obtained structure-property correlations are used to predict morphotropic phase boundaries and transition temperatures in as yet unsynthesized solid solutions.