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Title: Low temperature dielectric relaxation in ordinary perovskite ferroelectrics: enlightenment from high-energy x-ray diffraction

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
FOREIGN
OSTI Identifier:
1368322
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physics. D, Applied Physics; Journal Volume: 50; Journal Issue: 20
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Ochoa, D. A., Levit, R., Fancher, C. M., Esteves, G., Jones, J. L., and García, J. E.. Low temperature dielectric relaxation in ordinary perovskite ferroelectrics: enlightenment from high-energy x-ray diffraction. United States: N. p., 2017. Web. doi:10.1088/1361-6463/aa6b9e.
Ochoa, D. A., Levit, R., Fancher, C. M., Esteves, G., Jones, J. L., & García, J. E.. Low temperature dielectric relaxation in ordinary perovskite ferroelectrics: enlightenment from high-energy x-ray diffraction. United States. doi:10.1088/1361-6463/aa6b9e.
Ochoa, D. A., Levit, R., Fancher, C. M., Esteves, G., Jones, J. L., and García, J. E.. Wed . "Low temperature dielectric relaxation in ordinary perovskite ferroelectrics: enlightenment from high-energy x-ray diffraction". United States. doi:10.1088/1361-6463/aa6b9e.
@article{osti_1368322,
title = {Low temperature dielectric relaxation in ordinary perovskite ferroelectrics: enlightenment from high-energy x-ray diffraction},
author = {Ochoa, D. A. and Levit, R. and Fancher, C. M. and Esteves, G. and Jones, J. L. and García, J. E.},
abstractNote = {},
doi = {10.1088/1361-6463/aa6b9e},
journal = {Journal of Physics. D, Applied Physics},
number = 20,
volume = 50,
place = {United States},
year = {Wed Apr 26 00:00:00 EDT 2017},
month = {Wed Apr 26 00:00:00 EDT 2017}
}
  • We report that ordinary ferroelectrics exhibit a second order phase transition that is characterized by a sharp peak in the dielectric permittivity at a frequency-independent temperature. Furthermore, these materials show a low temperature dielectric relaxation that appears to be a common behavior of perovskite systems. Tetragonal lead zirconate titanate is used here as a model system in order to explore the origin of such an anomaly, since there is no consensus about the physical phenomenon involved in it. Crystallographic and domain structure studies are performed from temperature dependent synchrotron x-ray diffraction measurement. Results indicate that the dielectric relaxation cannot bemore » associated with crystallographic or domain configuration changes. The relaxation process is then parameterized by using the Vogel–Fulcher–Tammann phenomenological equation. Finally, results allow us to hypothesize that the observed phenomenon is due to changes in the dynamic behavior of the ferroelectric domains related to the fluctuation of the local polarization.« less
  • Graphical abstract: - Highlights: • Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-based ternary ferroelectric ceramics were prepared by solid-state synthesis method. • Morphotropic phase boundary region has been determined by XRD, di-/piezoelectric properties. • The compositions near MPB region exhibit excellent piezoelectric properties. - Abstract: A new compositional system of relaxor ferroelectrics was investigated based on the high piezoelectricity Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}–PbTiO{sub 3} ferroelectric perovskite family. Compositions were fabricated near an estimated morphotropic phase boundary (MPB) of the Pb(Lu{sub 1/2}Nb{sub 1/2})O{sub 3}–Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}–PbTiO{sub 3} (PLZNT) ternary system by a two-step synthetic process. Their structures have been analyzed by means ofmore » X-ray diffraction technique. On the basis of X-ray powder diffraction, the morphotropic phase boundary (MPB) region for the ternary system was obtained. The Curie temperature T{sub C} of ternary system varied from 240 °C to 330 °C and the coercive fields E{sub c}s > 10 kV/cm. The values of piezoelectric coefficients d{sub 33} vary in the range of 260–450 pC/N with different PZN contents. It is worth noting that the optimum compositions were located at MPB region but near the tetragonal phase. The new PLZNT ceramics exhibit wider range of T{sub C}s and E{sub c}s, making it a promising material for high-powder ultrasound transducers using in a large temperature range.« less
  • Low-temperature sintering of Pb(Zr,Ti)O{sub 3} (PZT) ceramics has been performed with the aid of oxyfluoride additives in order to compensate the volatilization of PbO, which results in the degradation of electric properties. An additive of a mixture of PbO and PbF{sub 2} (eutectic composition) realizes a liquid-phase sintering and allows high densification at low temperature. The densification of more than 98% of theoretical density was achieved by sintering at 900 C. The characterization of these PZT ceramics was carried out with XRD, TG, SEM, and dielectric measurements. The thermal variation of dielectric constant showed ferroelectric behavior. The highest permittivity valuemore » was obtained in the specimen fired at 900 C for 3 or 5 h with 3 wt% additive.« less
  • The structural, thermal and dielectric properties of YCrO{sub 3} ceramic prepared by solid state reaction method have been investigated by a combination of XRD, Raman spectroscopy and permittivity measurement. The X-ray diffraction spectra shows single phase orthorhombically distorted perovskite structure with Pnma symmetry over a wide range of temperature 300K to 1100K. Impedance spectroscopy study on the sample showed that the dielectric constant, tangent loss and ac conductivity with frequency increases on increasing the temperature. Dielectric measurement shows a relaxor like transition at about 460K. Non-Debye type relaxation is observed with activation energy of 0.25 eV extracted from ac conductivitymore » at 11 kHz frequency. We believe that the oxygen ion vacancies play an important role in conduction processes in addition to polaron hopping at higher temperatures. Raman scattering measurements were performed over a wide temperature range from 300K to 600 K. The line width of the modes due to CrO{sub 6} bending and in-plane O{sub 2} stretching broadens with increasing temperature.« less