Phase Coexistence Near a Morphotropic Phase Boundary in Sm-doped BiFeO3 Films

TL;DR

This study investigates phase coexistence in Sm-doped BiFeO3 films near a morphotropic boundary, revealing temperature-dependent phase crossover and strain effects on structural transitions.

Contribution

It provides detailed insights into phase coexistence and strain effects in Sm-doped BiFeO3 films near a morphotropic phase boundary using synchrotron X-ray diffraction.

Findings

Substantial phase coexistence observed during temperature-induced transition.

Thicker films show a volume collapse associated with the structural transition.

Strained thin films suppress the volume collapse seen in thicker films.

Abstract

We have investigated heteroepitaxial films of Sm-doped BiFeO3 with a Sm-concentration near a morphotropic phase boundary. Our high-resolution synchrotron X-ray diffraction, carried out in a temperature range of 25C to 700C, reveals substantial phase coexistence as one changes temperature to crossover from a low-temperature PbZrO3-like phase to a high-temperature orthorhombic phase. We also examine changes due to strain for films greater or less than the critical thickness for misfit dislocation formation. Particularly, we note that thicker films exhibit a substantial volume collapse associated with the structural transition that is suppressed in strained thin films.