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

Abstract

Piezoelectric materials play a key role in applications, while there are physically open questions. The physical origin of piezoelectricity is understood as the sum of contributions from intrinsic effects on lattice dynamics and those from extrinsic effects on ferroic‐domain dynamics, but there is an incomplete understanding that all but intrinsic effects are classified as extrinsic effects. Therefore, the accurate classification of extrinsic effects is important for understanding the physical origin of piezoelectricity. In this work, high‐energy synchrotron radiation X‐ray diffraction is utilized to measure the response of BiFeO3−BaTiO3 piezoelectrics and the intrinsic/extrinsic contribution to electric fields. It is found from crystal structure and intrinsic/extrinsic contribution, using the analysis involving structure refinement with various structural model and micromechanics‐based calculations, that Bi3+‐ion disordering is important for realization of piezoelectricity and nanodomains. Here, an extrinsic effect on the rearrangement of nanodomains is suggested. The nanodomains, which are formed by the locally distorted structure around the A‐site by Bi‐ion disordering, can significantly deform the material in the BiFeO3−BaTiO3 system, which contributes to the piezoelectric actuation mechanism apart from the extrinsic effect on ferroic‐domain dynamics. Bi‐ion disordering plays an important role in realizing piezoelectricity and nanodomains and can provide essential material design clues to develop next‐generation Bi‐based lead‐free piezoelectric ceramics.

Influence of temperature-induced A-site cation redistribution on the functional properties of A-site complex polar perovskite K1/2Bi1/2TiO3

“…Interestingly, at the higher symmetry cubic phase, the preferred displacement of Bi 3+ is the 〈100〉 c directions; however, during the transition to the tetragonal phase with cooling, the local Bi-displacement branch off to 〈111〉 c directions and induces local scale structural heterogeneity. 12 Kim et al 73 has attributed such local scale heterogeneity of Bi 3+ cation as the origin of nano-domains in Bi-based compositions. It is important to mention that existence of nano-domains does not necessarily indicate the presence of PNRs.…”

Bulk photovoltaic effect in ferroelectrics

“…The strong offcentering of the constituent atoms provides a large P s exceeding 100 μC cm −2 . 92) Owning to its attractive features, many researchers have investigated the ferroelectric, 93,94) magnetic, [95][96][97] piezoelectric, [98][99][100][101] capacitive, 102) and structural [103][104][105][106] properties of BFO and its solid solutions. The relatively small E g coexisting with the massive P s has motivated us to investigate their fundamental PV properties 4,16,22,56,107,108) and to develop PV devices.…”

Investigation of Praseodymium Ions Dopant on 9/65/35 PLZT Ceramics’ Behaviors, Prepared by the Gel-Combustion Route

“…The model proposed by the author implies that those local polar regions distort in the direction of the applied field within multiple local symmetries (pseudosymmetry) without long-range correlation. The nanodomain formation in the BF−BT system is associated with Bi 3+ ions off-centering [61], because bismuth has single-pair electrons that can lead to asymmetric distortions and off-center shifts. Therefore, ferroelectric behavior in lead-free materials is associated with realizing structure nanodomains by the off-center Bi ions [62].…”