Intrinsic versus extrinsic effects of the grain boundary on the properties of ferroelectric nanoceramics

Abstract

As the grain size decreases to the nanometer range, the characteristics of the ferroelectric nanoceramic can be ultimately determined by the competition between two effects: the intrinsic effect that is associated with the local properties of the grain boundary and the extrinsic effect that arises from the dynamics of domain structure which is highly influenced by the depolarization field caused by the grain boundary. In this work we investigate such a competition with a phase-field simulation based on the time-dependent Ginzburg-Landau (TDGL) kinetic equation.The study is performed on poled/unpoled nanoceramics under high-and low-amplitude bipolar alternating electric field with selected grain size and loading frequency. Our calculations for poled BaTiO 3 at 100 Hz show that, for the grain size from 170 to 50 nm, its properties are dominated by the extrinsic effect, and from 50 to 10 nm, they are dominated by the intrinsic one. As the grain size decreases, the dielectric and piezoelectric constants at the remnant state continuously rise in the extrinsic-dominated region and then drop sharply in the intrinsic-dominated region. Our frequency calculations from 10 to 2,500 Hz at the grain size of 100 nm indicate that the high-frequency behavior is very similar to that of the small grain-size, intrinsic-dominated one, whereas the low-frequency behavior is closely related to that of the large grain-size, extrinsic-dominated part, with the demarcation line occurring around 400 Hz. For the un-poled ceramics under small signal loading, the intrinsic effect is dominant over the entire range of grain size and frequency.

Effects of grain boundary and grain orientation on electrical behavior of polycrystalline ferroelectric field effect transistor

“…Some parallel polarization vectors can be identified, but near the grain boundary, there are some 90° domain walls. A similar phenomenon also occurs in Su et al , which is highly influenced by the depolarization field caused by the grain boundary. We also find that the coercive field at point B1 in Fig.…”

“…(c). Another reason is that the grain boundary leads to a large built‐in depolarizing field in grains . The possessive voltage of ferroelectric layer ( V f ) occupied from total voltage ( V g ) becomes larger, which causes a reduction of the surface potential ( ψ s ) on the semiconductor substrate.…”

Super-coercive electric field hysteresis in ferroelectric plastic crystal tetramethylammonium bromotrichloroferrate(iii)

“…[41][42][43][44][45][46][47][48] However, extrinsic factors such as interfacial properties, residual stress, chemical defects and structural defects (including grain boundaries) can also have a huge influence on domain switching. 35,[49][50][51][52][53][54][55][56][57] The significant influence of extrinsic factors is perhaps best manifested by the fact that real Ec values determined experimentally from hysteresis measurements are typically much smaller (<10 %) than the intrinsic values predicted by Landau-Ginzburg theory. 45 As a result, the frequency dependence of ferroelectric hysteresis measurements can provide valuable information concerning the domain kinetics and type of extrinsic factors that are dominant in a ferroelectric.…”

“…51 A similar oval or kidney-like shape is predicted at high frequencies by phase field models based on the time dependent Ginzburg-Landau kinetic equation and is caused by incomplete reversal of the polarization vectors. 41,55 Models show that the effect is exaggerated by internal stress and the volume of the material that is impacted by grain boundaries, which then Postprint version of the paper by Walker et al, in J. Mater.…”

Direct and converse nonlinear magnetoelectric coupling in multiferroic composites with ferromagnetic and ferroelectric phases

“…There have been considerable studies on the nonlinear behaviours of ferroelectric single crystals and polycrystals [56][57][58][59][60][61][62][63]. Phase field simulations have further revealed more in-depth microstructures evolution [64][65][66][67][68][69]. In the present approach, we will take a thermodynamics-based micromechanics approach to study the evolution of ferroelectric domain for the ferroelectric layer.…”