scholarly journals Comment on “Giant electromechanical coupling of relaxor ferroelectrics controlled by polar nanoregion vibrations”

2019 ◽  
Vol 5 (3) ◽  
pp. eaar5066 ◽  
Author(s):  
P. M. Gehring ◽  
Zhijun Xu ◽  
C. Stock ◽  
Guangyong Xu ◽  
D. Parshall ◽  
...  
Keyword(s):  
Acoustic Phonon ◽  
Electromechanical Coupling ◽  
Relaxor Ferroelectrics ◽  
Alternative Interpretation ◽  
Relaxor Ferroelectric ◽  
Lattice Vibrations ◽  
Phonon Branch ◽  
Transverse Acoustic ◽  
Neutron Wavelength ◽  
Polar Nanoregions

Manley et al. (Science Advances, 16 September 2016, p. e1501814) report the splitting of a transverse acoustic phonon branch below TC in the relaxor ferroelectric Pb[(Mg1/3Nb2/3)1−xTix]O3 with x = 0.30 using neutron scattering methods. Manley et al. argue that this splitting occurs because these phonons hybridize with local, harmonic lattice vibrations associated with polar nanoregions. We show that splitting is absent when the measurement is made using a different neutron wavelength, and we suggest an alternative interpretation.

scholarly journals Response to comment on “Giant electromechanical coupling of relaxor ferroelectrics controlled by polar nanoregion vibrations”

2019 ◽  
Vol 5 (3) ◽  
pp. eaaw4367
Author(s):  
M. E. Manley ◽  
D. L. Abernathy ◽  
A. D. Christianson ◽  
J. W. Lynn
Keyword(s):  
Multiple Scattering ◽  
Electromechanical Coupling ◽  
Time Of Flight ◽  
Relaxor Ferroelectrics ◽  
Relaxor Ferroelectric ◽  
Instrument Resolution ◽  
Scattering Geometry ◽  
Transverse Acoustic

Gehring et al. argue that a splitting observed by us in the transverse acoustic (TA) phonon in the relaxor ferroelectric Pb[(Mg1/3Nb2/3)1−xTix]O3 with x = 0.30 (PMN-30PT) is caused by a combination of inelastic-elastic multiple scattering processes called ghostons. Their argument is motivated by differences observed between their measurements made on a triple-axis spectrometer and our measurements on a time-of-flight spectrometer. We show that the differences can be explained by differences in the instrument resolution functions. We demonstrate that the multiple scattering conditions proposed by Gehring et al. do not work for our scattering geometry. We also show that, when a ghoston is present, it is too weak to detect and therefore cannot explain the splitting. Last, this phonon splitting is just one part of the argument, and the overall conclusion of the original paper is supported by other results.

Dynamics of Central Peaks in the Brillouin Scattering Spectra of Relaxor Ferroelectrics

2009 ◽  
Vol 421-422 ◽  
pp. 403-406
Author(s):  
Ghulam Shabbir ◽  
Seiji Kojima
Keyword(s):  
High Resolution ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Brillouin Scattering ◽  
Relaxor Ferroelectrics ◽  
Relaxor Ferroelectric ◽  
Subsequent Growth ◽  
Scattering Technique ◽  
Scattering Spectra ◽  
Polar Nanoregions

High-resolution Brillouin scattering technique was applied to study the dynamics of central peaks (CPs) in two relaxor ferroelectric systems, PLZT-x/65/35 ceramics and PMN-33%PT [001] single crystals, respectively. It was found that CPs appear very close to an intermediate temperature, Td, for both type of specimens. The temperature dependence of CPs was attributed to the appearance and subsequent growth of polar nanoregions (PNRs) intrinsic to relaxor materials.

scholarly journals Giant electromechanical coupling of relaxor ferroelectrics controlled by polar nanoregion vibrations

2016 ◽  
Vol 2 (9) ◽  
pp. e1501814 ◽  
Author(s):  
Michael E. Manley ◽  
Douglas L. Abernathy ◽  
Raffi Sahul ◽  
Daniel E. Parshall ◽  
Jeffrey W. Lynn ◽  
...  
Keyword(s):  
Local Structure ◽  
Electromechanical Coupling ◽  
Collective Motion ◽  
Piezoelectric Materials ◽  
Relaxor Ferroelectrics ◽  
Piezoelectric Response ◽  
Atomic Displacements ◽  
Electromechanical Responses ◽  
Polar Nanoregions ◽  
Ultrasound Applications

Relaxor-based ferroelectrics are prized for their giant electromechanical coupling and have revolutionized sensor and ultrasound applications. A long-standing challenge for piezoelectric materials has been to understand how these ultrahigh electromechanical responses occur when the polar atomic displacements underlying the response are partially broken into polar nanoregions (PNRs) in relaxor-based ferroelectrics. Given the complex inhomogeneous nanostructure of these materials, it has generally been assumed that this enhanced response must involve complicated interactions. By using neutron scattering measurements of lattice dynamics and local structure, we show that the vibrational modes of the PNRs enable giant coupling by softening the underlying macrodomain polarization rotations in relaxor-based ferroelectric PMN-xPT {(1 − x)[Pb(Mg1/3Nb2/3)O3] – xPbTiO3} (x = 30%). The mechanism involves the collective motion of the PNRs with transverse acoustic phonons and results in two hybrid modes, one softer and one stiffer than the bare acoustic phonon. The softer mode is the origin of macroscopic shear softening. Furthermore, a PNR mode and a component of the local structure align in an electric field; this further enhances shear softening, revealing a way to tune the ultrahigh piezoelectric response by engineering elastic shear softening.

Magnons and Phonons in Cobalt Ferrite

1974 ◽  
Vol 52 (5) ◽  
pp. 396-398 ◽  
Author(s):  
H. C. Teh ◽  
M. F. Collins ◽  
H. A. Mook
Keyword(s):  
Acoustic Phonon ◽  
Room Temperature ◽  
Cobalt Ferrite ◽  
Zone Boundary ◽  
Phonon Branch ◽  
Longitudinal Acoustic ◽  
Transverse Acoustic ◽  
Low Energies ◽  
Longitudinal Acoustic Phonon ◽  
Infrared Data

Magnons and phonons have been observed in a single crystal of cobalt ferrite, CoFe2O1 at room temperature. Dispersion relations are plotted for the [001] and the [111] directions. The longitudinal acoustic phonon branch has been measured out to the zone boundary in both directions, while the transverse acoustic branch has been completely determined only in the [001] direction. The acoustic magnon branches are well defined at low energies, but they rapidly lose intensity and disappear at around 9 THz. We have not determined uniquely why this happens, but some possibilities are given. Optic branches have been observed at around 11.3 and 14.0 THz. Infrared data indicate that the first branch is probably of phonon character and the second of magnon character.

Local atomic structure of relaxor ferroelectric solids studied by pulsed neutron scattering

1994 ◽  
Vol 52 ◽  
pp. 554-555
Author(s):  
T. Egami ◽  
H. D. Rosenfeld ◽  
S. Teslic
Keyword(s):  
Neutron Scattering ◽  
Atomic Structure ◽  
Argonne National Laboratory ◽  
Relaxor Ferroelectrics ◽  
Relaxor Ferroelectric ◽  
Crystallographic Structure ◽  
Chemical Inhomogeneity ◽  
Distribution Analysis ◽  
Ferroelectric Transition ◽  
Pulsed Neutron

Relaxor ferroelectrics, such as Pb(Mg1/3Nb2/3)O3 (PMN) or (Pb·88La ·12)(Zr·65Ti·35)O3 (PLZT), show diffuse ferroelectric transition which depends upon frequency of the a.c. field. In spite of their wide use in various applications details of their atomic structure and the mechanism of relaxor ferroelectric transition are not sufficiently understood. While their crystallographic structure is cubic perovskite, ABO3, their thermal factors (apparent amplitude of thermal vibration) is quite large, suggesting local displacive disorder due to heterovalent ion mixing. Electron microscopy suggests nano-scale structural as well as chemical inhomogeneity.We have studied the atomic structure of these solids by pulsed neutron scattering using the atomic pair-distribution analysis. The measurements were made at the Intense Pulsed Neutron Source (IPNS) of Argonne National Laboratory. Pulsed neutrons are produced by a pulsed proton beam accelerated to 750 MeV hitting a uranium target at a rate of 30 Hz. Even after moderation by a liquid methane moderator high flux of epithermal neutrons with energies ranging up to few eV’s remain.

scholarly journals Implications of acceptor doping in the polarization and electrocaloric response of 0.9Pb(Mg1/3Nb2/3)O3–0.1PbTiO3 relaxor ferroelectric ceramics

2021 ◽  
Vol 9 (9) ◽  
pp. 3204-3214
Author(s):  
Andraž Bradeško ◽  
Marko Vrabelj ◽  
Lovro Fulanović ◽  
Šarūnas Svirskas ◽  
Maksim Ivanov ◽  
...  
Keyword(s):  
Relaxor Ferroelectrics ◽  
Relaxor Ferroelectric ◽  
Ferroelectric Ceramics ◽  
Acceptor Doping ◽  
Defect Engineering ◽  
Relaxor Ferroelectric Ceramics

Defect engineering by acceptor doping affects the dipolar state in relaxor ferroelectrics, resulting in a tailored electrocaloric response.

scholarly journals Piezoelectric polar nanoregions and relaxation-coupled resonances in relaxor ferroelectrics

2018 ◽  
Vol 98 (13) ◽  
Author(s):  
Ling Cai ◽  
Radha Pattnaik ◽  
Joel Lundeen ◽  
Jean Toulouse
Keyword(s):  
Relaxor Ferroelectrics ◽  
Polar Nanoregions

scholarly journals Phase instability induced by polar nanoregions in a relaxor ferroelectric system

2008 ◽  
Vol 7 (7) ◽  
pp. 562-566 ◽  
Author(s):  
Guangyong Xu ◽  
Jinsheng Wen ◽  
C. Stock ◽  
P. M. Gehring
Keyword(s):  
Relaxor Ferroelectric ◽  
Phase Instability ◽  
Polar Nanoregions

scholarly journals Ultralow thermal conductivity from transverse acoustic phonon suppression in distorted crystalline α-MgAgSb

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiyang Li ◽  
Peng-Fei Liu ◽  
Enyue Zhao ◽  
Zhigang Zhang ◽  
Tatiana Guidi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Acoustic Phonon ◽  
Transverse Acoustic
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