Article abstract
Nature Materials 7, 562 - 566 (2008)
Published online: 11 May 2008 | doi:10.1038/nmat2196
Subject Categories: Ceramics | Electronic materials
Phase instability induced by polar nanoregions in a relaxor ferroelectric system
Guangyong Xu1, Jinsheng Wen1,2, C. Stock3 & P. M. Gehring4
Abstract
Relaxor ferroelectrics are a special class of material that exhibit an enormous electromechanical response and are easily polarized with an external field. These properties make them attractive for applications as sensors and actuators. Local clusters of randomly oriented polarization, known as polar nanoregions (PNRs), are specific to relaxor ferroelectrics and play a key role in governing their dielectric properties. Here, we show through neutron inelastic scattering experiments that the PNRs can also significantly affect the structural properties of the relaxor ferroelectric Pb(Zn1/3Nb2/3)O3-4.5%PbTiO3 (PZN-4.5%PT). A strong interaction is found between the PNRs and the propagation of acoustic phonons. A comparison between acoustic phonons propagating along different directions reveals a large asymmetry in the lattice dynamics that is induced by the PNRs. We suggest that a phase instability induced by this PNR–phonon interaction may contribute to the ultrahigh piezoelectric response of this and related relaxor ferroelectric materials. Our results naturally explain the emergence of the various observed monoclinic phases in these systems.
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
- Department of Materials Science, State University of New York, Stony Brook, New York 11794, USA
- Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6100, USA
Correspondence to: Guangyong Xu1 e-mail: gxu@bnl.gov
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