Nonlinear dielectric property for (1-x)Ba(Ti<inf>0.88</inf>Sn<inf>0.12</inf>)O<inf>3</inf>-x(Ba<inf>0.7</inf>Ca<inf>0.3</inf>)TiO<inf>3</inf> ceramics

Abstract

Dielectric ceramics have been widely used for actuators, capacitors, and sensors. However, the nonlinearity of its dielectric property obstacles the usage of precise control. In this paper, the functional dielectrics Ba(Ti _0.88 Sn _0.12 )O ₃ -x(Ba _0.7 Ca _0.3 )TiO ₃ (x=0.2-0.4) (abbreviated as BTS-BCT) have been investigated to improve its linearity. Dielectric properties were investigated by Rayleigh law under sub-switching electric field. The result shows that dielectric behavior of this system can be well analyzed by Rayleigh law. The total dielectric permittivity consists of intrinsic and extrinsic contributions. The intrinsic polarization response caused by lattice deformation exhibits peak values in the vicinity of composition-induced morphotropic phase boundary (MPB), but being much less than total permittivity value. Nevertheless, the extrinsic response which contribute more than half of total permittivity changes sharply with composition, and the extrinsic parameter of x=0.4 composition is about 10% of x=0.2. It suggests that the dielectric response of the tetragonal phase shows more linearity than the rhombohedral phase.