Nonlinear dielectric properties of Ba1-xSrxTiO3 ceramics

In the present paper the electric field dependence of the permittivity of (Ba, Sr)TiO3 ceramics is reported. Single phase Ba1-xSrxTiO3 (x = 0.20 and 0.30) ceramics were obtained by powders synthesized by a modified Pechini method. The dc-tunability at room temperature is higher for the ceramic with lower strontium content as this composition is ferroelectric at room temperature, whereas the composition corresponding to the higher strontium content is paraelectric. The data are well described by the Johnson's approximation for the ferroelectric state and by an additional extrinsic contribution due to the polar clusters in the case of the paraelectric state (Ba, Sr)TiO3 ceramic. (C) 2009 Elsevier B.V. All rights reserved.