Complex phase mixture and domain superstructure across a new lead-free ferroelectric/anti-ferroelectric morphotropic phase boundary

TL;DR

This study explores the microstructural evolution and phase transition mechanisms in a lead-free ferroelectric/antiferroelectric material, revealing how compositional changes induce a shift from ferroelectric to antiferroelectric phases.

Contribution

It provides new insights into the microstructural evolution and phase transition pathways in Bi(1-x)SmxFeO3, combining experimental electron diffraction analysis with kinetic Monte Carlo simulations.

Findings

Sm3+ substitution induces antiferroelectricity via short-range cation displacements.

Increasing Sm content strengthens anti-parallel interactions, driving phase transition.

Oxygen octahedra tilts induce complete antiferroelectricity in certain composition range.

Abstract

We investigate the microstructural evolution in a ferroelectric to antiferroelectric phase transition at the morphotropic phase boundary in the Bi(1-x)SmxFeO3 system. Continuous Sm3+ substitution on the A-site induces short-range anti-parallel cation displacements as verified by the appearance of localized 1/4(110) weak spots in selected area electron diffraction patterns for 0.1<x<0.14 samples, and thus onset of antiferroelectricity. Kinetic Monte Carlo simulations confirm that increasing the strength of the anti-parallel interactions (i.e. increasing x) induces a ferroelectric to antiferroelectric transition. For 0.14<x<0.2 antiphase oxygen octahedra tilts induce complete antiferroelectricity.