Phonon coupling to dynamic short-range polar order in a relaxor ferroelectric near the morphotropic phase boundary
- Author(s): Schneeloch, JA
- Xu, Z
- Winn, B
- Stock, C
- Gehring, PM
- Birgeneau, RJ
- Xu, G
- et al.
Published Web Locationhttps://doi.org/10.1103/PhysRevB.92.214302
© 2015 American Physical Society. We report neutron inelastic scattering experiments on single-crystal PbMg1/3Nb2/3O3 doped with 32% PbTiO3, a relaxor ferroelectric that lies close to the morphotropic phase boundary. When cooled under an electric field E∥  into tetragonal and monoclinic phases, the scattering cross section from transverse acoustic (TA) phonons polarized parallel to E weakens and shifts to higher energy relative to that under zero-field-cooled conditions. Likewise, the scattering cross section from transverse optic (TO) phonons polarized parallel to E weakens for energy transfers 4≤ω≤9 meV. However, TA and TO phonons polarized perpendicular to E show no change. This anisotropic field response is similar to that of the diffuse scattering cross section, which, as previously reported, is suppressed when polarized parallel to E but not when polarized perpendicular to E. Our findings suggest that the lattice dynamics and dynamic short-range polar correlations that give rise to the diffuse scattering are coupled.
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