Dielectric properties under dc-bias field of Ba0.6Sr0.4TiO3 with various grain sizes

We study the effect of grain size on the dc field dependence of dielectric characteristics in Ba0.6Sr0.4TiO3 ceramics prepared by a sol-gel method. The samples were observed and analysed by SEM and X-ray diffraction. The dielectric constant samples decreases as the applied dc field increases. The influence of the de field on the loss factor is much less than that on the dielectric constant. With increasing of the applied voltage, the T-c was increased and the peaks were suppressed and broadened. As the grain size increases, The maximum dielectric constant and the percentage change of dielectric constant under a dc field increase. A transition broadening and shift of T-c are observed as grain size decreases. (C) 2002 Elsevier Science B.V. All rights reserved.