A Theory of D-E Hysteresis Loop Based on the Avrami Model

Polarization dynamics across the morphotropic phase boundary in Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 ferroelectrics

“…The problem of analysis is that polycrystalline ferroelectrics typically exhibit a complicated dispersive switching response which cannot be interpreted in terms of the classical nucleation and growth theory often referred to as the Kolmogorov-Avrami-Ishibashi (KAI) model. 3 To obtain microscopic parameters providing the macroscopic switching process, more sophisticated theories are required, which account for a statistical distribution of local switching times in a system. [4][5][6][7][8] To this end, the inhomogeneous field mechanism (IFM) model is used in this paper, which derives the distribution of times from the distribution of randomly distributed local field values.…”

“…Traditionally, the polarization switching kinetics is described by the KAI model, 3 which suggests a temporal dependence of the reversed polarization as follows:…”

Strain Mechanisms in Lead-Free Ferroelectrics for Actuators

“…143,144 It is noted that the removal of the electric field leads to a decay of 65 % in the polarization of BNT-0.25ST, indicating that although in BNT-0.25ST is higher than in BNT-0.28ST, it still has considerably lower values than its . Domain switching is a time-dependent kinetic process 73,[441][442][443] , while a first order phase transition is an infinitely fast discontinuous process occurring in the terahertz range. 39,48,444 Therefore, a feasible way to give insight into the nature of the phase transition and the origin of the volume change is to perform polarization and strain measurements at a rate faster than the time domain where the switching processes should occur.…”

“…242 Although, the induced phase transition is of first order, the subsequent switching of the domains formed is a kinetic process that requires time. 73,[441][442][443] Therefore, it is expected that each sub-cycle allows a gradual increase in the amount of switching. The gradual increase of the values after each sub-cycle is analogous to the increase of the values observed with increasing field strength in pulse experiments ( Figure 5.46).…”

“…Therefore, increasing electric field above − leads to saturation. Since switching is a thermally activated kinetic process 73,[441][442][443] , the macroscopic observation of the anomalies ascribed to the development of the ferroelectric long-range order in the small and large signal properties depends on frequency. Since the small signal properties under bias-field were measured with a 0.05 Hz large signal base waveform (Section 4.4.2.2), inherent differences are expected with the large signal results performed at 1 Hz.…”