Phase field simulations of the poling process and nonlinear behavior of ferroelectric polycrystals with semiconducting grain boundaries

Abstract

The effect of grain boundary conductivity on the poling process and the nonlinear electromechanical behaviors of ferroelectric polycrystals are investigated through the use of a phase field model. The grain boundary is modeled as a semiconductor in the phase field model via Maxwell’s equations, which consider the drift of free charges under an electric field. The simulation results show that the poling electric field of the ferroelectric polycrystal with the semiconducting grain boundary is much larger than that of an insulating grain boundary, which is due to the screening of polarization-induced charges at the grain boundaries. The P-E hysteresis loop becomes narrow, and the ferroelectric property degrades in the presence of a semiconducting grain boundary; this indicates that the grain boundary conductivity has a significant influence on the nonlinear behavior of the ferroelectric polycrystals. On the other hand, the grain boundary conductivity, however, has less effect on the response of the ferroelectric polycrystals to a mechanical load. The present work provides an insight into the effect of the charge leakage, which is induced by the material defects, e.g., the grain boundary, on the electromechanical properties of piezoelectric ceramics.

Understanding, Predicting, and Designing Ferroelectric Domain Structures and Switching Guided by the Phase-Field Method

“…A phasefield model of polycrystal ferroelectrics was first proposed by Choudhury et al (99), and similar models were later applied to study the effects of grain orientation (104), grain boundary width (64), and grain boundary semiconduction (105) on switching behaviors. Generally, the P-E loop shrinks with a decrease in grain size and with an increase in grain misorientation (61) and can be largely tilted and diminished if the grain boundary becomes conductive (105). Recently, Su and coworkers (63,100,106) further examined this topic by systematically investigating the grain size effect with finer grains down to 10 nm under cyclic fields with a frequency of up to 2,500 Hz.…”

Phase-field modeling of domain evolution in ferroelectric materials in the presence of defects

“…In what follows, we refer to the free energy density for lead-titanate (PbTiO 3 ), which is a ferroelectric material with cubic symmetry, widely discussed in the literature (see, e.g. [54][55][56][57]59] and [34,51,61,64]).…”

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

“…Actually, the structure of ferroelectric thin films in FeFETs is generally polycrystalline film which is composed of grain boundary and grain orientation. The grain boundary and grain orientation have a significant effect on the C–V relation curve and the output characteristic curve of FeFETs through the remnant polarization value and the coercive field of ferroelectric films . It has been reported that hysteresis loops with different grain orientations are distinguishing, particularly in their coercive fields .…”