Stochastic model of dispersive multi-step polarization switching in ferroelectrics due to spatial electric field distribution

Abstract

A stochastic model for polarization switching in tetragonal ferroelectric ceramics is introduced, which includes sequential 90 • -and parallel 180 • -switching processes and accounts for the dispersion of characteristic switching times due to a nonuniform spatial distribution of the applied field. It presents merging of the recent multistep stochastic mechanism (MSM) with the earlier nucleation limited switching (NLS) and inhomogeneous field mechanism (IFM) models. The new model provides a much better description of simultaneous polarization and strain responses over a wide time window and a deeper insight into the microscopic switching mechanisms, as is exemplarily shown by comparison with measurements on lead zirconate titanate. a) Electronic address:

Multistep stochastic mechanism of polarization reversal in rhombohedral ferroelectrics

“…Particularly, the analysis revealed a substantial contribution of the fast processes, which do not cause macroscopic spontaneous strain and exhibit characteristics of non-180° switching events. Such coherent non-180° switching processes were indirectly identified in previous studies [34,37,38] and recently directly observed optically [64]. This is in agreement with a general conclusion from molecular dynamics that 180°-switching in tetragonal ceramics proceeds rather via sequential 90°-domain wall motion [25].…”

“…reflects the scaling properties of the polarization response observed on various bulk polycrystalline ferroelectrics [8,9,10,[34][35][36][37].…”

“…It is known, on the other hand, that fast non-180° processes may occur in a coherent way, so that their average macroscopic strain vanishes, and thus mimic the 180°-switching [63]. Such quasi-180° processes were indirectly identified in the electromechanical response of tetragonal PZT, with characteristic times typical of 90°-events [34,37], and of rhombohedral PZT, with characteristic times typical of 71°-events [38]. Very recently, such synchronized 90°-domain switching processes were directly observed by Zhu et al during electric field loading of a barium titanate single crystal by using a fast camera combined with a polarized light microscope [64].…”

“…the electrostriction coefficient 11 0.0302 Q  m 4 /C 2 derived from Fig.4. The best fitting parameters common for all applied fields are to the parameters of tetragonal PZT[37] and BNT-BT[61], respectively.…”

Crystal Orientations Dependent Polarization Reversal in Ferroelectric PbZr0.2Ti0.8O3 Thin Films for Multilevel Data Storage Applications

“…In that study, they observed different switching regimes in the dynamics during polarization reversal, which lead to name such type of switching as multiswitching states. [25,26] To understand the polarization reversal behavior with increase in [111] miscut angle, the evolution of polarization reversal with different magnitude of write voltage in different PZT crystal directions is carried out as shown in Figure 4a,b, and also in Figures S11-S22 in the Supporting Information. Figure 4a shows the VPFM phase scans for different switching voltages on the [416]/[111] 29.27° starting from the pristine state.…”