Field-Induced Ferroelectric Phase Transition Dynamics in PMN-PT compositions near the Morphotropic Phase Boundary

TL;DR

This study investigates how PMN-PT near the MPB exhibits field-induced ferroelectric phase transitions whose kinetics are strongly governed by field-temperature history. Using FC-FH and ZFC protocols on two near-MPB compositions (x ≈ 0.289, 0.295), the work reveals history-dependent Tc, delayed nucleation times τ_ZFC, and polarization memory, with aging in non-ferroelectric states slowing transitions and repetitive cycling overcoming this damping. A key finding is the emergence of a glassy-like short-range order that competes with long-range ferroelectric order, producing a non-Arrhenius slowdown and a pronounced dependence on aging temperature and duration; this can be reversed or accelerated by specific cycling strategies, enabling kinetic enhancement and self-organization in zero field. The results advance understanding of relaxor-ferroelectric dynamics near the MPB and have implications for designing field-assisted switching in PMN-PT-based devices, where history effects could be harnessed or mitigated to control ferroelectric ordering.

Abstract

The dynamical behavior of field-induced ferroelectric phase transitions in compositions of PbMg_{1/3}Nb_{2/3}O3(1-x)-PbTiO3(x), called PMN-PT, near the Morphotropic Phase Boundary (MPB) was investigated through several different external electrical field application protocols. Our results indicate that the phase transitions in PMN-PT compositions near the MPB behave differently than in compositions far below the MPB. We show that the electrical-field history has a notable impact on the field-induced transition temperature T_c, ZFC delay time tau_{ZFC}, and induced polarization P_c, gained/lost during field-induced phase transition. Moreover, we demonstrate that under certain field-temperature conditions PMN-PT can retain its electrical field history and use it to kinetically accelerate its ferroelectric ordering. An explanation for the key difference between the phase transition dynamics in compositions near and far from the MPB is proposed and contextualized within prior publications.

Figures (10)

• Figure 1: An empirical concentration-temperature phase diagram for PMN-PT adopted from Zekria05. Phase II represents the Morphotropic Phase Boundary for PMN-PT. Phase I typically represents the Pseudo-cubic/Rhombohedral ferroelectric state, while Phase III typically represents the Tetragonal ferroelectric state. On the phase diagram, the colored dashed lines represent the concentration of each sample that was studied.
• Figure 2: (a) FC-FH Regime Protocol; (b) Polarization current responses during FC and FH.
• Figure 3: Empirical field-induced temperature-electrical field phase diagrams are shown for (a) PMN-PT composition with x $\sim$ 0.12 (adopted from Colla2007) and (b) for PMN-PT composition with x $\sim$ 0.295. Two cooling lines are plotted for two different cooling rates: 4 K/min and 0.5 K/min. The difference between these cooling lines is plotted as as a function of DC electrical field strength in the insets.
• Figure 4: (a) Intermediate Field-Aging step protocol is shown as temperature and external electrical field strength as functions of time. (b) The field-induced polarization current in FC#2 is plotted against the continuous measurement of temperature for different aging times ranging from 0 to 2 hours. (c) Characteristic curves of field-induced phase transition temperatures are plotted as a function of the aging time for four different aging temperatures.
• Figure 5: (a) Certain time slices of the different return point experimental protocol are shown. (b) The empirical field-induced ferroelectric phase transition temperature is plotted against the return point temperatures. Four return point temperatures are circled in both (a) and (b). The inset graph plots the induced polarization current for the four circled points against temperature. (c) The polarization gained (marked in blue) and lost (marked in red) in field-induced phase transitions is graphed as a function of return point temperature.