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Materials Research

Print version ISSN 1516-1439

Abstract

SANTOS, I.A.; ARANTES, V.L.; GARCIA, D.  and  EIRAS, J.A.. Transição de Fase Difusa e Propriedades Dielétricas de Cerâmicas Ferroelétricas de (Pb, Ba)Nb2O6. Mat. Res. [online]. 2002, vol.5, n.1, pp. 13-19. ISSN 1516-1439.  http://dx.doi.org/10.1590/S1516-14392002000100003.

Tungsten bonze structured lead barium niobate (Pb1-xBaxNb2O6) ferroelectric ceramics were prepared by the conventional mixed oxide method and their dielectric properties were carefully investigated. All studied samples presented elevated values of maximum dielectric constant (e'm) and its corresponding temperature of maximum (Tm) in comparison with perovskite structured ones. The phase transition features indicate that the PBN samples do not present a complete diffuse phase transition. Indeed, the diffuseness degree of the ferroelectric phase transition is highly dependent of the ions Pb2+ content in the sample compositions. The diffuseness of the ferroelectric phase transition is enhanced while the temperature of maximum dielectric constant is decreased with the Pb2+ content decreasing. In addition, the maximum dielectric constant shows an opposite behavior.

Keywords : diffuse phase transition; electroceramics; niobates.

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