Origin of the "Waterfall" Effect in Phonon Dispersion of Relaxor Perovskites

Abstract

Inelastic neutron scattering study of the perovskite relaxor ferroelectric PZN:8%PT elucidates the origin of the previously reported unusual kink on the low frequency transverse phonon dispersion curve (known as "waterfall" effect). We show that its position depends on the choice of the Brillouin zone and that the relation of its position to the size of the polar nanoregions is highly improbable. The observation is explained in the framework of a simple model of coupled damped harmonic oscillators representing the acoustic and optic phonon branches.

4 pages, 6 figures, LaTeX

References in corpus (5)

• Phase diagram of the relaxor ferroelectric (1-x)PbZn(1/3)Nb(2/3)O3-xPbTiO3
• Soft Mode Dynamics Above and Below the Burns Temperature in the Relaxor Pb(Mg_1/3Nb_2/3)O_3
• Mode-coupling and polar nanoregions in the relaxor ferroelectric Pb(Mg1/3Nb2/3)O3
• Direct evidence of soft mode behavior near the Burns' temperature in PbMg${}_{1/3}$Nb${}_{2/3}$O${}_3$ (PMN) relaxor ferroectric
• Anomalous transverse acoustic phonon broadening in the relaxor ferroelectric Pb(Mg_1/3Nb_2/3)O_3

Cited by in corpus (32)

• Giant Anharmonic Phonon Scattering in PbTe
• Phase instability induced by polar nanoregions in a relaxor ferroelectric system
• The role of random electric fields in relaxors
• Central mode and soft mode behavior in PbMg1/Nb2/3O3 relaxor ferroelectric
• Cold neutron scattering study on diffuse and phonon excitations in the relaxor PbMg(1/3)Nb(2/3)O3
• Damped Soft Phonons and Diffuse Scattering in 40PMN-60PT
• Soft phonon columns on the edge of the Brillouin zone in the relaxor PbMg1/3Nb2/3O3
• Quasi-Elastic Scattering, Random Fields and phonon-coupling effects in PbMg1/3Nb2/3O3
• Insight into dielectric response of ferroelectric relaxors by statistical modeling
• Strong Influence of the diffuse component on the lattice dynamics in Pb(Mg${}_{1/3}$Nb${}_{2/3}$)O${}_3$
• Phase transitions and ferroelectrics: revival and the future in the field
• Grain Size Influence on Dynamics of Polar Nanoclusters in PMN-35%PT Ceramics: Broadband Dielectric and Infrared Spectra
• Ab initio linear response and frozen phonons for the relaxor PMN (PbMg1/3Nb2/3O3)
• The influence of elastic strain gradient on the upper limit of flexocoupling strength, spatially-modulated phases and soft phonon dispersion in ferroics
• Dielectric relaxation and polar phonon softening in relaxor ferroelectric PbMg_(1/3)Ta_(2/3)O_3
• Missed surface waves in non-piezoelectric solids
• Phonon broadening from supercell lattice dynamics: random and correlated disorder
• Evidence for anisotropic polar nanoregions in relaxor PMN: A neutron study of the elastic constants and anomalous TA phonon damping
• Flexocoupling induced soft acoustic mode and the spatially modulated phases in ferroelectrics
• Non-adiabatic effects in the phonon dispersion of Mg 1--x Al x B 2
• Spontaneous decay of a soft optical phonon in the relaxor ferroelectric PbMg${}_{1/3}$Nb${}_{2/3}$O${}_3$
• Fluctuating defects in the incipient relaxor K${}_{1-x}$Li${}_x$TaO${}_3$ (x=0.02)
• Matryoshka Phonon Twinning in alpha-GaN
• Transverse acoustic phonon anomalies at intermediate wavevectors in MgV${}_2$O${}_4$
• Origins of large enhancement in electromechanical coupling for nonpolar directions in ferroelectric BaTiO3
• Size effect of soft phonon dispersion law in nanosized ferroics
• Electric field effect on short-range polar orders in a relaxor ferroelectric system
• Broadband critical dynamics in disordered lead-based perovskites
• Phonon coupling to dynamic short-range polar order in a relaxor ferroelectric near the morphotropic phase boundary
• Fast broadband cluster spin-glass dynamics in PbFe${}_{1/2}$Nb${}_{1/2}$O${}_3$
• Probing phonon softening in ferroelectrics by the scanning probe microwave spectroscopy
• Microscopic flexoelectricity in the canonical PMN relaxor