Phase instability induced by polar nanoregions in a relaxor ferroelectric system

Abstract

Local inhomogeneities known as polar nanoregions (PNR) play a key role in governing the dielectric properties of relaxor ferroelectrics - a special class of material that exhibits an enormous electromechanical response and is easily polarized with an external field. Using neutron inelastic scattering methods, we show that the PNR 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 PNR and the propagation of sound waves, i.e. acoustic phonons, the visibility of which can be enhanced with an external electric field. A comparison between acoustic phonons propagating along different directions reveals a large asymmetry in the lattice dynamics that is induced by the PNR. 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 also naturally explain the emergence of the various observed monoclinic phases in these systems.

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• Piezoelectric Response and Free Energy Instability in the Perovskite Crystals BaTiO3, PbTiO3 and Pb(Zr,Ti)O3
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• Tripling energy storage density through order-disorder transition induced polar nanoregions in PbZrO3 thin films by ion implantation
• A two-component model of the neutron diffuse scattering in the relaxor ferroelectric PZN-4.5%PT
• Deep data mining in a real space: Separation of intertwined electronic responses in a lightly-doped BaFe2As2
• Response of polar nanoregions in 68%Pb(Mg1/3Nb2/3)O3-32%PbTiO3 to a [001] electric field
• Polaron-mediated spin correlations in metallic and insulating La${}_{1-x}{A}_x$MnO${}_3$ ($A$=Ca, Sr, or Ba)
• Freezing of the local dynamics in the relaxor ferroelectric PZN-4.5PT
• Role of Zinc and Niobium in the Giant Piezoelectric Response of PbZn1/3Nb2/3O3