Design of superior electrostriction in BaTiO₃‐based lead‐free relaxors via the formation of polarization nanoclusters

Abstract

Electrostrictive materials have wide applications in modern high-precision electronic devices. Driven by growing environmental concerns, there is demand for lead-free materials with superior electrostriction behaviors. In this study, we demonstrate a record-high electrostrictive coefficient of ~0.0712 m 4 C À2 in perovskite ferroelectric ceramics, along with hysteresis-free strain as well as excellent frequency and thermal stabilities, in lead-free BaTiO 3 -based ceramics through a polarization nanocluster design. By appropriately introducing Li + and Bi 3+ into the BaTiO 3 lattice matrix, the longrange ferroelectric ordering can be broken, and polarization nanoclusters can be formed, resulting in a relaxor state with concurrently suppressed polarization and maintained electro-strain. A three-dimensional atomic model constructed using advanced neutron total-scattering data combined with the reverse Monte Carlo method indicates the existence of Bi and Li segregations at the subnanometer scale, which confirms the prediction made by density functional theory calculations. Such a short-range chemical order destroys the long-range ferroelectric order of the off-centered Ti polar displacements and leads to the embedding of Li + /Bi 3+ -rich polar nanoregions in the Ba 2+ -rich polarization disorder matrix. Further, a completely reversible electric-fieldinduced lattice strain is observed, giving rise to pure electrostriction without hysteresis behavior. This work provides a novel strategy for developing leadfree relaxor ferroelectrics with high electrostriction performance.

Emergence of high piezoelectricity from competing local polar order-disorder in relaxor ferroelectrics

“…Crystal structure based on long-range periodicity with randomly distributed species provides excellent convenience in describing crystalline solids' properties. Yet, emerging functional crystalline materials usually harbor locally correlated disorder that is deviated from the global long-range average structure, such as that with respect to the composition or atomic displacements [1][2][3][4] . Critically, such structural disorder has a profound impact on their functional properties.…”

Superior Capacitive Energy-Storage Performance in Pb-Free Relaxors with a Simple Chemical Composition

“…The atomic-resolution displacement mapping gives the direct 2D distribution, but cannot provide the relation between local chemical and polar inhomogeneity. Interestingly, the atomic PDF based on total scattering is a tool that can offer quantitative information about local and subnanoscale structures. , The recent advances in big-box structure-refinement methodology enable to establish a 3D atomic configuration directly by fitting the experimental total scattering data. − To construct the 3D nanoscale structure of BBT12, both neutron and X-ray total scattering data were collected. A big-box atomic configuration with 20 × 20 × 20 perovskite unit cells (40,000 atoms, approximately 80 × 80 × 80 Å 3 ) was refined according to a RMC algorithm by simultaneously fitting six experimental data, including neutron-based and X-ray-based reciprocal-space S ( Q ) data and real-space PDF G ( r ) data, and Bragg data.…”

Time-dependent theory of optical electro- and magnetostriction

“…We also point out that most theoretical and experimental studies of the static electro-and magnetostriction correspond to the thermodynamical equilibrium limit. Experimental studies of electrostriction have also revealed interesting phenomena, such as the giant electrostriction [15][16][17][18][19][20][21][22][23][24][25], negative electrostriction [26,27], and deformations of liquid crystals [28,29] and biological cells [30]. On the theoretical side, electrostriction has also been under extensive study [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48].…”