Morphotropic Phase Boundary in Sm-Substituted BiFeO3 Ceramics: Local vs Microscopic Approaches

TL;DR

This study investigates the structural phase transitions in Sm-substituted BiFeO3 ceramics across the morphotropic phase boundary using local and microscopic techniques, revealing phase coexistence and differences in boundary estimation.

Contribution

It provides a detailed comparison of local and microscopic measurement techniques to analyze phase coexistence in Sm-doped BiFeO3 ceramics, highlighting differences in phase boundary estimation.

Findings

Identification of phase coexistence regions in the composition range 0.12 < x < 0.18.

Microscopic techniques suggest a wider phase coexistence range than local measurements.

Structural transitions from rhombohedral to orthorhombic phases confirmed.

Abstract

Samarium substituted bismuth ferrite (BiFeO3) ceramics prepared by sol-gel synthesis method were studied using both local scale and microscopic measurement techniques in order to clarify an evolution of the crystal structure of the compounds across the morphotropic phase boundary region. X-ray diffraction analysis, transmission and scanning electron microscopies, XPS, EDS/EDX experiments and piezoresponse force microscopy were used to study the structural transitions from the polar active rhombohedral phase to the anti-polar orthorhombic phase and then to the non-polar orthorhombic phase, observed in the Bi1-xSmxFeO3 compounds within the concentration range of 0.08 < x < 0.2. The results obtained by microscopic techniques testify that the compounds in the range of 0.12 < x < 0.15 are characterized by two phase structural state formed by a coexistence of the rhombohedral and the anti-polar orthorhombic phases; two phase structural state observed in the compounds with 0.15 < x < 0.18 is associated with a coexistence of the anti-polar orthorhombic and the non-polar orthorhombic phases. Local scale measurements have revealed a notable difference in the concentration range ascribed to the morphotropic phase boundary estimated by microscopic measurements, the obtained results testify a wider concentration range ascribed to a coexistence of different structural phases, the background of the mentioned difference is discussed.