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

Autor(es)

Camilo Albornoz Diaz, Julio Cesar ^{[1, 2]} ; M'Peko, Jean-Claude ^[3] ; Venet, Michel ^[1] ; da Silva Jr, Paulo Sergio

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: SCIENTIFIC REPORTS; v. 10, n. 1 NOV 10 2020.
• Citações Web of Science: 0

Resumo

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)

• Processo FAPESP: 13/00134-7 - Obtenção e aprimoramento das propriedades de compósitos magnetoelétricos livres de chumbo
• Beneficiário: Michel Venet Zambrano
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 17/17872-1 - Novos compósitos magnetoelétricos livres de chumbo com alta performance
• Beneficiário: Michel Venet Zambrano
• Modalidade de apoio: Bolsas no Exterior - Pesquisa
• Processo FAPESP: 20/10446-0 - Desvendando a resposta dielétrica de alta temperatura do Bi0.5Na0.5TiO3
• Beneficiário: Paulo Sergio da Silva Junior
• Modalidade de apoio: Auxílio à Pesquisa - Publicações científicas - Artigo
• Processo FAPESP: 12/08457-7 - Estudo das transições de fases de cerâmicas piezoelétricas livres de chumbo por espectroscopia mecânica
• Beneficiário: Paulo Sergio da Silva Junior
• Modalidade de apoio: Auxílio à Pesquisa - Regular