First-principles investigation of morphotropic transitions and phase-change functional responses in BiFeO3-BiCoO3 multiferroic solid solutions

TL;DR

This study uses first-principles calculations to explore phase transitions and functional responses in BiFeO3-BiCoO3 solid solutions, revealing large phase-change effects and potential electric field switching capabilities.

Contribution

It provides the first ab initio analysis of morphotropic transitions in BFCO solid solutions, identifying stable phases and their switchable properties.

Findings

Discontinuous morphotropic transition between BFO-like and BCO-like phases.

Stable and distinguishable phases across compositions.

Large phase-change effects including piezoelectric, electric, and magnetoelectric responses.

Abstract

We present an ab initio study of the BFCO solid solution formed by multiferroics BiFeO3 (BFO) and BiCoO3 (BCO). We find that BFCO presents a strongly discontinuous morphotropic transition between BFO-like and BCO-like ferroelectric phases. Further, for all compositions such phases remain (meta)stable and retain well-differentiated properties. Our results thus suggest that an electric field can be used to switch between these structures, and show that such a switching involves large phase-change effects of various types, including piezoelectric, electric, and magnetoelectric ones.