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Title: Persistence and memory of polar nanoregions in a ferroelectric relaxor under an electric field

Abstract

The response of polar nanoregions (PNR) in the ferroelectric relaxor Pb[(Zn{sub 1/3}Nb{sub 2/3}){sub 0.92}Ti{sub 0.08}]O{sub 3} subject to a [111]-oriented electric field has been studied by neutron diffuse scattering. Contrary to classical expectations, the diffuse scattering associated with the PNR persists, and is even partially enhanced, after field cooling. The effect of the external electric field is retained by the PNR after the field is removed. The 'memory' of the applied field reappears even after heating the system above the Curie temperature T{sub C} and cooling in zero field.

Authors:
;  [1];  [2]
  1. Physics Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)
  2. NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)
Publication Date:
OSTI Identifier:
20787738
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 72; Journal Issue: 21; Other Information: DOI: 10.1103/PhysRevB.72.214106; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COOLING; CURIE POINT; DIFFUSE SCATTERING; ELECTRIC FIELDS; FERROELECTRIC MATERIALS; HEATING; LEAD COMPOUNDS; NANOSTRUCTURES; NEUTRON DIFFRACTION; NIOBIUM COMPOUNDS; TITANATES; ZINC COMPOUNDS

Citation Formats

Xu Guangyong, Shirane, G., and Gehring, P.M. Persistence and memory of polar nanoregions in a ferroelectric relaxor under an electric field. United States: N. p., 2005. Web. doi:10.1103/PHYSREVB.72.2.
Xu Guangyong, Shirane, G., & Gehring, P.M. Persistence and memory of polar nanoregions in a ferroelectric relaxor under an electric field. United States. doi:10.1103/PHYSREVB.72.2.
Xu Guangyong, Shirane, G., and Gehring, P.M. Thu . "Persistence and memory of polar nanoregions in a ferroelectric relaxor under an electric field". United States. doi:10.1103/PHYSREVB.72.2.
@article{osti_20787738,
title = {Persistence and memory of polar nanoregions in a ferroelectric relaxor under an electric field},
author = {Xu Guangyong and Shirane, G. and Gehring, P.M.},
abstractNote = {The response of polar nanoregions (PNR) in the ferroelectric relaxor Pb[(Zn{sub 1/3}Nb{sub 2/3}){sub 0.92}Ti{sub 0.08}]O{sub 3} subject to a [111]-oriented electric field has been studied by neutron diffuse scattering. Contrary to classical expectations, the diffuse scattering associated with the PNR persists, and is even partially enhanced, after field cooling. The effect of the external electric field is retained by the PNR after the field is removed. The 'memory' of the applied field reappears even after heating the system above the Curie temperature T{sub C} and cooling in zero field.},
doi = {10.1103/PHYSREVB.72.2},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 21,
volume = 72,
place = {United States},
year = {Thu Dec 01 00:00:00 EST 2005},
month = {Thu Dec 01 00:00:00 EST 2005}
}
  • The response of polar nanoregions (PNR) in the ferroelectric relaxor Pb[(Zn1/3Nb2/3)0.92Ti0.08]O3 subject to a [111]-oriented electric field has been studied by neutron diffuse scattering. Contrary to classical expectations, the diffuse scattering associated with the PNR persists, and is even partially enhanced, after field cooling. The effect of the external electric field is retained by the PNR after the field is removed. The 'memory' of the applied field reappears even after heating the system above the Curie temperature T{sub C} and cooling in zero field.
  • Relaxor ferroelectrics1, which are utilized as actuators and sensors2-4, exemplify a class of poorly understood materials where interplay between disorder and phase instability results in inhomogeneous nanoregions. There is no definitive explanation for the onset of relaxor behavior (Burns temperature5, Td) or the origin of polar nanoregions (PNRs). Here we show a vibrational mode that localizes on cooling to Td, remains localized as PNRs form, and then delocalizes as PNRs grow using neutron scattering on relaxor (Pb(Mg1/3Nb2/3)O3)0.69-(PbTiO3)0.31 (PMN-31%PT). Although initially appearing like intrinsic local modes (ILMs)6-10, these modes differ below Td as they form a resonance with the ferroelectric phonon.more » At the resonance, nanoregions of standing ferroelectric phonons develop with a coherence length matching the PNRs. The size, shape, distribution, and temporal fluctuations of PNRs, and our observations, are explained by ferroelectric phonons trapped by disordered resonance modes via Anderson localization11-13. Our results show the size and shape of PNRs are not dictated by complex structural details, as always assumed, but by a phonon resonance wavevector. This simplification could guide the design of next generation relaxors.« less
  • Relaxor ferroelectrics, with their strong dependence of polarization on the applied electric field, are of considerable technological importance. On a microscopic scale, however, there exists competition as well as coexistence between short-range and long-range polar order. The conventional picture is that the polar nano-regions (PNRs) that appear at high temperatures beyond the Curie transition, form nuclei for the field-induced long-range order at low temperatures. Here, we report high-energy X-ray diffuse-scattering measurements on the relaxor Pb(Zn(1/3)Nb(2/3))O(3) (PZN) to study the short-range polar order under an electric field applied along the [111] direction. In contrast to conventional expectations, the overall diffuse-scattering intensitymore » is not suppressed. On the other hand, the field induces a marked change on the shape of the three-dimensional diffuse-scattering intensity pattern, corresponding to a redistribution of PNRs in real space. We show that these surprising results are consistent with a model in which the PNRs with [110]-type polarizations, orthogonal to that of the surrounding environment, are embedded and persist in the [111]-polarized ferroelectric order of the bulk.« less
  • The complex structure of relaxor ferroelectrics comprises polar nanoregions (PNRs) which appear upon cooling below the Burns temperature and quenched compositional (chemical) disorder. The relation between the polar nanostructure and compositionally ordered regions (CORs) often observed in relaxors has been the subject of extensive theoretical investigations; however, the experimental data, especially concerning Pb(B0 1=3B00 2=3)O3-type complex perovskite relaxors, are rather limited. In this paper, we analyse and discuss the results of our recent investigations of the morphology of CORs and the dynamics of PNRs in Pb(Mg1/3Nb2/3)O3-based solid solutions in which the degree of compositional disorder was varied by means ofmore » changing the composition and/or by means of high-temperature annealing. The samples were characterised using X-ray diffraction, transmission electron microscopy, piezoresponse force microscopy, Brillouin light scattering, dielectric spectroscopy, as well as by measuring pyroelectric effect and ferroelectric hysteresis loops. No influence of the size of CORs on the PNRs relaxation in the ergodic relaxor phase is found. Instead, the CORs size influences significantly the diffuseness of the transition from the field-induced ferroelectric phase to the ergodic relaxor state. The results are interpreted in the framework of a model suggesting the coexistence of static and dynamic PNRs in the ergodic relaxor phase.« less