Polarization reversal via a transient relaxor state in nonergodic relaxors near freezing temperature  

作　　者：Chang-Hyo Hong Hanzheng Guo Xiaoli Tan John E.Daniels Wook Jo 

机构地区：[1]School of Materials Science and Engineering,Ulsan National Institute of Science and Technology,Ulsan,44919,Republic of Korea [2]Department of Materials Science and Engineering,Iowa State University,Ames,IA,50011,USA [3]School of Materials Science and Engineering,University of New South Wales,New South Wales,2052,Australia

出　　处：《Journal of Materiomics》2019年第4期634-640,共7页无机材料学学报（英文）

基　　金：the financial support by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2018R1D1A1B07051176);the financial support by the National Science Foundation(NSF)through Grant DMR-1700014;the financial support from the ARC Discovery Project Scheme.

摘　　要：Among the unresolved issues in the study of relaxor ferroelectrics is the role of freezing temperature,across which the dynamics of polarization reversal in relaxor ferroelectrics changes.The presence of this freezing temperature is best manifested by the appearance of a double polarization hysteresis loop just above the freezing temperature.Given that the polarization pinching evolving into a double hysteresis starts well below the freezing temperature,there exists a transient temperature regime between the nonergodic and the ergodic relaxor states.To clarify the role of the freezing temperature on the pinching,the polarization reversal near the freezing temperature of relaxor(Pb_(1-x)La_(x))(Zr_(1-y)T_(y))_(1-x/4)O_(3)(PLZT)was monitored using three in situ electric field methods:electrocaloric effect,neutron diffraction,and transmission electron microscopy.We demonstrate that the pinching results from a two-step process,1)domain detexturization in the ferroelectric state and 2)miniaturization of domains.This observation explains the recently reported gap between the depolarization temperature T_(d) and the ferroelectric-torelaxor transition temperature T_(F-R) in lead-free relaxors.We further show that T_(d) and T_(F-R),which have long been considered identical in lead-based relaxors,are not the same.The current study suggests that the mismatch between T_(d) and TF-R is an inherent feature in both lead-based and lead-free relaxor ferroelectrics.

关 键 词：Relaxor NANODOMAINS In situ Neutron diffraction Transmission electron microscopy 

分 类 号：O18[理学—数学]