Disorder and relaxation mode in the lattice dynamics of PbMg_1/3Nb_2/3O₃ relaxor ferroelectric

2003/11/05 by S. N. Gvasaliya, S. G. Lushnikov, B. Roessli
Physics and Astronomy · #cond-mat.mtrl-sci

paper · pdf · doi:10.1103/physrevb.69.092105

published as Phys. Rev. B 69, 092105 (2004).

arxiv created 2003/11/05 · arxiv updated 2009/12/01

Abstract

The low-energy part of vibration spectrum in PbMg_1/3Nb_2/3O₃ relaxor ferroelectric was studied by inelastic neutron scattering. We observed the coexistence of a resolution-limited central peak with strong quasielastic scattering. The line-width of the quasielastic component follows a Γ₀+Dq² dependence. We find that Γ₀ is temperature-dependent. The relaxation time follows the Arrhenius law well. The presence of a relaxation mode associated with quasi-elastic scattering in PMN indicates that order-disorder behaviour plays an important rôle in the dynamics of diffuse phase transitions.

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