Artigo
Effect of the excess of bismuth on the morphology and properties of the BaBi2Ta2O9 ceramics
Fecha
2005-03-01Registro en:
Materials Letters. Amsterdam: Elsevier B.V., v. 59, n. 6, p. 656-661, 2005.
0167-577X
10.1016/j.matlet.2004.11.001
WOS:000226802500011
Autor
Universidade Estadual Paulista (Unesp)
Universidade Federal de São Carlos (UFSCar)
Resumen
In this study, the effect of bismuth content on the crystal structure, morphology and electric properties of barium-bismuth-tantalate (BBT) ceramics was explored with the aid of X-ray diffraction (XRD), scanning electron microcopy (SEM), dielectric properties and ferroelectric hysteresis loops. BaBi2Ta2O9 (BBT) ceramics have been successfully prepared by the solid-state reaction. The BBT phase was crystallized at 900 degreesC for 2 h. The excess of bismuth controls the grain size, affecting the density of the material. Measurements of dieletric constant and dieletric losses confirm that the material is a ferroeletric with a Curie temperature around 77 degreesC. The dieletric constant measured at room temperature was 400, with a dielectric loss of 0.03. Both the phase-transition behaviour and ferroelectric properties, such as spontaneous polarization (P-s), showed a dependence on Bi content. (C) 2004 Elsevier B.V. All rights reserved.