The Contributions of Polar Nanoregions to the Dielectric and Piezoelectric Responses in Domain‐Engineered Relaxor‐PbTiO₃ Crystals

Abstract

The existence of polar nanoregions is the most important characteristic of relaxor-based ferroelectric materials. Recently, the contributions of polar nanoregions to the shear piezoelectric property of relaxor-PbTiO 3 (PT) crystals are confirmed in a single domain state, accounting for 50%-80% of room temperature values. For electromechanical applications, however, the outstanding longitudinal piezoelectricity in domain-engineered relaxor-PT crystals is of the most significance. In this paper, the contributions of polar nanoregions to the longitudinal properties in [001]-poled Pb(Mg 1/3 Nb 2/3 )O 3 -0.30PbTiO 3 and [110]-poled Pb(Zn 1/3 Nb 2/3 )O 3 -0.15PbTiO 3 (PZN-0.15PT) domain-engineered crystals are studied. Taking the [110]-poled tetragonal PZN-0.15PT crystal as an example, phase-field simulations of the domain structures and the longitudinal dielectric/piezoelectric responses are performed. According to the experimental results and phase-field simulations, the contributions of polar nanoregions (PNRs) to the longitudinal properties of relaxor-PT crystals are successfully explained on the mesoscale, where the PNRs behave as "seeds" to facilitate macroscopic polarization rotation and enhance electric-field-induced strain. The results reveal the importance of local structures to the macroscopic properties, where a modest structural variation on the nanoscale greatly impacts the macroscopic properties.

High-Performance Sm-Doped Pb(Mg1/3Nb2/3)O3-PbZrO3-PbTiO3-Based Piezoceramics

“…Figure 7e,f shows the relationship of ln(f) and 1/T m for Sm-doped PMN-PZ-0.352PT and un-doped PMN-PZ-0.372PT ceramics, respectively. Obviously, they follow a linear relationship and are in good agreement with the Arrhenius law 13 f f E kT exp( / )…”

“…Figure e,f shows the relationship of ln­( f ) and 1/ T m for Sm-doped PMN-PZ-0.352PT and un-doped PMN-PZ-0.372PT ceramics, respectively. Obviously, they follow a linear relationship and are in good agreement with the Arrhenius law where f is the measurement frequency, k B is the Boltzmann constant, f 0 is the attempt frequency, and T m is the temperature of maximum value ε″/ε 0 . E a is the relaxation activation energy, being related to the re-orientating energy barrier density and volume of the local structural heterogeneity. , By fitting formula (eq ), the values of E a can be calculated to be on the order of 7.0 × 10 –20 and 5.1 × 10 –20 J for Sm-doped PMN-PZ-0.352PT and un-doped PMN-PZ-0.372PT ceramics, respectively.…”

Superior energy storage performance coupled with excellent electrical characteristics in lead-free Ba0.8Ca0.2TiO3-(Bi0.80Mg0.20) (Ti0.65Mg0.30)O3 ceramics

“…Therefore, the slim ferroelectric loop of BCT-BMT ceramics is ascribed to the existence of local polar crystals in the specimen, which agrees with our inference based on the increasing frequency dispersion in the dielectric constant of BCT-BMT samples. The transformation of BMT substituted samples into a relaxor ferroelectric is caused by the disruption in ferroelectric long-range ordering and subsequent occurrence of PNRs [24]. The obtained results are consistent with the dielectric characteristics, where a broad dielectric curve can be observed for higher concentration BCT-BMT samples.…”

Feasible Way to Achieve Multifunctional (K, Na)NbO3-Based Ceramics: Controlling Long-Range Ferroelectric Ordering

“…With the increasing x , f 0 and E a first decrease and then increase, while T VF first increases and then decreases (Figure c,d). f 0 values for the ceramics with x = 0.04–0.08 are within the range of 10 10 –10 12 Hz (Figure c), which are analogous to those of the Pb­(Mg 1/3 Nb 2/3 )­O 3 –PbTiO 3 (PMN–PT) ferroelectric relaxors and in accordance with the typical lattice vibration frequency . Interestingly, E a decreases from 0.04 eV (at x = 0.04) to 0.01 eV (at x = 0.05), then increases slowly to 0.06 eV (at x = 0.07), but rapidly jumps to 0.16 eV (at x = 0.08).…”