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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.)

Unveiling the high-temperature dielectric response of Bi0.5Na0.5TiO3

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Camilo Albornoz Diaz, Julio Cesar [1, 2] ; M'Peko, Jean-Claude [3] ; Venet, Michel [1] ; da Silva Jr, Paulo Sergio
Total Authors: 4
[1] Univ Fed Sao Carlos, Dept Phys, POB 676, BR-13565905 Sao Carlos, SP - Brazil
[2] Energy & Nucl Res Inst, Ctr Sci & Technol Mat, BR-05508170 Sao Paulo, SP - Brazil
[3] Univ Sao Paulo, Sao Carlos Inst Phys, POB 369, BR-13560970 Sao Carlos, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: SCIENTIFIC REPORTS; v. 10, n. 1 NOV 10 2020.
Web of Science Citations: 0

Understanding the physics behind changes in dielectric permittivity and mechanical response with temperature and frequency in lead-free ferroic materials is a fundamental key to achieve optimal properties and to guarantee good performance in the technological applications envisaged. In this work, dense Bi0.5Na0.5TiO3 (BNT) electroceramics were prepared through solid-state reaction of high-grade oxide reagents, followed by sintering at high temperature (1393 K for 3 h). In good agreement with previous reports in the literature, the thermal behaviour of dielectric response from these BNT materials showed the occurrence of a high-temperature diffuse-like permittivity peak, whose origin has been so far controversial. Thermally stimulated depolarization current, impedance and mechanical spectroscopies measurements were here conducted, over a wide range of temperature and frequency, to get a deep insight into the mechanism behind of this event. The approach included considering both as-sintered and reduced BNT samples, from which it is demonstrated that the broad high-temperature dielectric peak originates from interfacial polarization involving oxygen vacancies-related space-charge effects that develop at the grain-to-grain contacts. This mechanism, that contributes to the anomalous behavior observed in the mechanical response at low frequencies, could also be responsible for the presence of ferroelastic domains up to high temperatures. (AU)

FAPESP's process: 13/00134-7 - Obtaining and improvement of properties of lead free magnetoelectric composites
Grantee:Michel Venet Zambrano
Support Opportunities: Regular Research Grants
FAPESP's process: 17/17872-1 - New lead free magnetoelectric composites with high performance
Grantee:Michel Venet Zambrano
Support Opportunities: Scholarships abroad - Research
FAPESP's process: 12/08457-7 - Study of the phase transitions of the lead-free piezoceramics by mechanical spectroscopy
Grantee:Paulo Sergio da Silva Junior
Support Opportunities: Regular Research Grants