Combinatorial discovery of a lead-free morphotropic phase boundary in a thin-film piezoelectric perovskite

TL;DR

This paper reports the discovery of a lead-free morphotropic phase boundary in Sm-doped BiFeO3 thin films, showing promising piezoelectric properties comparable to traditional PZT, using a combinatorial thin film approach.

Contribution

It introduces a novel lead-free piezoelectric material with a morphotropic phase boundary discovered via combinatorial thin film strategy.

Findings

Identified a rhombohedral to pseudo-orthorhombic phase boundary in Sm-doped BiFeO3.

Achieved dielectric and piezoelectric properties comparable to PZT.

Proposed a lead-free alternative for piezoelectric applications.

Abstract

We report on the discovery of a lead-free morphotropic phase boundary in Sm doped BiFeO3 with a simple perovskite structure using the combinatorial thin film strategy. The boundary is a rhombohedral to pseudo-orthorhombic structural transition which exhibits a ferroelectric (FE) to antiferroelectric (AFE) transition at approximately Bi0.86Sm0.14FeO3 with dielectric constant and out-of-plane piezoelectric coefficient comparable to those of epitaxial (001) oriented Pb(Zr,Ti)O3 (PZT) thin films at the MPB. The discovered composition may be a strong candidate of a Pb-free piezoelectric replacement of PZT.