Quasi-Elastic Scattering, Random Fields and phonon-coupling effects in PbMg1/3Nb2/3O3

Abstract

The low-energy part of the vibration spectrum in PbMg${}_{1/3}$Nb${}_{2/3}$O${}_3$ (PMN) relaxor ferroelectric has been studied by neutron scattering above and below the Burns temperature, T${}_d$. The transverse acoustic and the lowest transverse optic phonons are strongly coupled and we have obtained a model for this coupling. We observe that the lowest optic branch is always underdamped. A resolution-limited central peak and quasi-elastic scattering appear in the vicinity of the Burns temperature. It is shown that it is unlikely that the quasi-elastic scattering originates from the combined effects of coupling between TA and TO phonons with an increase of the damping of the TO phonon below T${}_d$. The quasi-elastic scattering has a peak as a function of temperature close to the peak in the dielectric constant while the intensity of the central peak scattering increases strongly below this temperature. These results are discussed in terms of a random field model for relaxors.

References in corpus (13)

• Polarized Raman study of the phonon dynamics in Pb(Mg${}_{1/3}$Nb)O${}_3$ crystal
• Neutron Diffuse Scattering from Polar Nanoregions in the Relaxor Pb(Mg1/3Nb2/3)O3
• Soft Mode Dynamics Above and Below the Burns Temperature in the Relaxor Pb(Mg_1/3Nb_2/3)O_3
• Ferroelectric Ordering in the Relaxor Pb(Mg1/3Nb2/3)O3 as Evidenced by Low-Temperature Phonon Anomalies
• Soft Phonon Anomalies in the Relaxor Ferroelectric Pb(Zn_1/3Nb_2/3)_0.92Ti_0.08O_3
• Origin of the "Waterfall" Effect in Phonon Dispersion of Relaxor Perovskites
• Universal Static and Dynamic Properties of the Structural Transition in Pb(Zn1/3Nb2/3)O3
• Mode-coupling and polar nanoregions in the relaxor ferroelectric Pb(Mg1/3Nb2/3)O3
• Dynamical effects of the nanometer-sized polarized domains in Pb(Zn1/3Nb2/3)O3
• Cold neutron scattering study on diffuse and phonon excitations in the relaxor PbMg(1/3)Nb(2/3)O3
• Direct evidence of soft mode behavior near the Burns' temperature in PbMg${}_{1/3}$Nb${}_{2/3}$O${}_3$ (PMN) relaxor ferroectric
• Disorder and relaxation mode in the lattice dynamics of PbMg${}_{1/3}$Nb${}_{2/3}$O${}_3$ relaxor ferroelectric
• Soft Mode Anomalies in the Perovskite Relaxor Pb(Mg1/3Nb2/3)O3

Cited by in corpus (16)

• A reassessment of the Burns temperature and its relationship to the diffuse scattering, lattice dynamics, and thermal expansion in the relaxor PMN
• Damped Soft Phonons and Diffuse Scattering in 40PMN-60PT
• Interplay between static and dynamic polar correlations in relaxor Pb(Mg_{1/3}Nb_{2/3})O_{3}
• Neutron and X-ray diffraction study of cubic [111] field cooled Pb(Mg1/3Nb2/3)O3
• Soft phonon columns on the edge of the Brillouin zone in the relaxor PbMg1/3Nb2/3O3
• Random Electric Field Instabilities of Relaxor Ferroelectrics
• Paraelectric and Ferroelectric States in a Model for Relaxor Ferroelectrics
• Evidence for anisotropic polar nanoregions in relaxor PMN: A neutron study of the elastic constants and anomalous TA phonon damping
• The Structural Phase Transition of the Relaxor Ferroelectric 68%PbMg1/3Nb2/3O3-32%PbTiO3
• Evolution of the neutron quasi-elastic scattering through the ferroelectric phase transition in 93%PbZn${}_{1/3}$Nb${}_{2/3}$O${}_3$ - 7% PbTiO${}_3$
• Structure Factor of a Relaxor Ferroelectric
• Anomalous pressure dependence of the atomic displacements in the relaxor ferroelectric PbMg${}_{1/3}$Ta${}_{2/3}$O${}_3$
• Relaxation of dynamically disordered tetragonal platelets in the relaxor ferroelectric $0.964{\mathrm{Na}}_{1/2}{\mathrm{Bi}}_{1/2}{\mathrm{TiO}}_3-0.036{\mathrm{BaTiO}}_3$
• Broadband critical dynamics in disordered lead-based perovskites
• Fast broadband cluster spin-glass dynamics in PbFe${}_{1/2}$Nb${}_{1/2}$O${}_3$
• Coexisting ferroelectric and antiferroelectric phases in dipole ordered substances. Material properties and possible applications