Lead-Free BiFeO3-Based Piezoelectrics: A Review of Controversial Issues and Current Research State

Abstract

Lead-free electroceramics represent an emerging area of research that has the potential to enable new green advances in electronics. Research has mainly focused on the development of new piezoelectric materials for replacing lead containing oxides exhibiting superior electromechanical behavior. Lead-free BiFeO3-based materials are not only the promising candidates to replace lead-based materials but also show intriguing properties which may inspire innovative material design for the next generation of lead-free piezoceramics. This review aims to highlight the current state of research and overlooked aspects in lead-free BiFeO3-based ceramics, which could be insightful in elucidating certain controversial issues. Current strategies to reduce high conductivity, influence of chemical heterogeneity on both functional properties and crystal structure, effective heat treatment procedures, and the role of pseudo-cubic structures on the enhancement of piezoelectric properties are subjects of highlighted within this review as they have a significant impact on the quality of BiFeO3-based lead-free piezoelectrics (but are often disregarded).

Composition dependence of structural and piezoelectric properties in Bi(Mg0.5Ti0.5)O3-modified BaTiO3-BiFeO3 ceramics

“…10,18,19,25,36) Furthermore, the combination of relaxorlike BT-BMT with nano-sized domains and ferroelectric BF with macro-sized domains is similar to the complex domain structure exhibited by several BTBF-based relaxor ferroelectrics. 11,12,14,32,38) Based on the analysis of the structural characteristics and overall electrical properties, the 33BTBF-BMT series was found to be a relaxor ferroelectric characteristics with pseudo-cubic crystal symmetry. Here, a relatively high small-signal d 33 was achieved at 33BTBF-BMT series among all of the studied compositions.…”

Piezoelectric Actuation Mechanism Involving Extrinsic Nanodomain Dynamics in Lead‐Free Piezoelectrics

“…In this study, we determined the actuation mechanism of piezoelectricity and the origin of nanodomain structures in lead-free BF−BT piezoelectrics, which are considered as the promising alternative of lead-based piezoelectrics. [19,21,31] Crystallographic structures averaged over long distances in the samples were determined using SR-XRD experiments. The intrinsic and extrinsic contributions to the macroscopic electrostrain were resolved quantitatively and reported in terms of both the absolute and relative contributions.…”

“…The major issue, the origin of piezoelectricity in the pseudocubic phase, has been intensively discussed in BF-BT and BF-BT-based system. [21] To understand the mechanism of piezoelectricity in a pseudocubic structure, various models have been suggested for Bi-based materials. [22][23][24] The centrosymmetry of a cubic structure changes to a lower symmetry of a tetragonal structure under an electric field, [22,23] which is called an electric-field-induced phase transition.…”

Fabrication of 〈100〉-oriented Bi(Mg0.5Ti0.5)O3-modified BiFeO3-BaTiO3 ceramics and their piezoelectric properties

“…Pb-free BiFeO 3 -BaTiO 3 (BFBT)-based piezoelectric ceramics are strong candidates for replacing Pb-based piezoelectric ceramics, owing to their relatively large piezoelectric response with a high Curie temperature. [1][2][3][4] Among them, we investigated the various ferroelectric and relaxor ferroelectric-like piezoelectric and ferroelectric properties in Bi(Mg 0.5 Ti 0.5 )O 3 (BMT)-modified BFBT systems through a chemical composition dependence. 2) Specifically, the composition range of (1−y) {xBT(1−x)BF}yBMT, where x = 0.25, 0.30, 0.33, and 0.40, and y = 0.01, 0.03, 0.05, and 0.10, was explored.…”