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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Spontaneous long and short-range ferroelectric ordering in Pb0.55La0.30TiO3 ceramics

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Author(s):
Mastelaro, V. R. [1] ; Mascarenhas, Y. P. [1] ; Neves, P. P. [2] ; Mir, M. [2] ; Doriguetto, A. C. [2] ; Michalowicz, A. [3, 4] ; Moscovici, J. [3, 4] ; Lente, M. H. [5] ; Eiras, J. A. [5]
Total Authors: 9
Affiliation:
[1] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13560970 Sao Paulo - Brazil
[2] Univ Fed Alfenas UNIFAL MG, Lab Cristalog, BR-37130000 Alfenas, MG - Brazil
[3] CNRS, Inst Chim & Mat Paris Est, F-94320 Thiais - France
[4] Univ Paris Est Creteil, F-94320 Thiais - France
[5] Univ Fed Sao Carlos UFSCar, Dept Fis, BR-13565670 Sao Paulo - Brazil
Total Affiliations: 5
Document type: Journal article
Source: Journal of Applied Physics; v. 107, n. 11 JUN 1 2010.
Web of Science Citations: 5
Abstract

In this work, we investigated the temperature dependence of short and long-range ferroelectric ordering in Pb0.55La0.30TiO3 relaxor composition. High-resolution x-ray powder diffraction measurements revealed a clear spontaneous macroscopic cubic-to-tetragonal phase transition in the PLT relaxor sample at similar to 60 K below the maximum of the dielectric constant peak (T-m). Indeed, the x-ray diffraction (XRD) data showed that at 300 K (above T-m but below the Burns temperature, T-B) the long-range order structure corresponds to a macroscopic cubic symmetry, space group number 221 (Pm-3m), whereas the data collected at 20 K revealed a macroscopic tetragonal symmetry, space group number 99 (P4mm) with c/a=1.0078, that is comparable to that of a normal ferroelectric. These results show that for samples with tetragonal composition, the long-range ferroelectric order may be recovered spontaneously at cryogenics temperatures, in contrast to ferroelectric samples with rhombohedral symmetry. On the other hand, x-ray absorption spectroscopy investigations intriguingly revealed the existence of local tetragonal disorder around Ti atoms for temperatures far below T-m and above T-B, for which the sample presents macroscopic tetragonal and cubic symmetries, respectively. (C) 2010 American Institute of Physics. {[}doi: 10.1063/1.3431024] (AU)

FAPESP's process: 00/09722-9 - Ferroelectric materials: phenomenology, properties and characterization
Grantee:José Antonio Eiras
Support type: Research Projects - Thematic Grants