Dielectric ferroelectric and piezoelectric properties of BaTi0.975(Zn1/3Nb2/3)0.025O3 ceramic

The present work concerns the preparation, dielectric, ferroelectric and piezoelectric characterizations of the lead-free ceramic composition BaTi0.97(Zn1/3Nb2/3)(0.025)O-3. This lead-free composition could be of great interest for environment friendly applications (dielectric for capacitors, actuators, etc.). This ceramic was prepared using the conventional mixed-oxide technique. The temperature dependence of the dielectric constant of this composition BaTi0.975(Zn1/3Nb2/3)(0.025)O-3 was investigated. The rhombohedral-orthorhombic and orthorhombic-quadratic perovskite transitions are characterized by two weak peaks but the tetragonal-cubic ferroelectric-paraelectric one is characterized by a pronounced peak with weak frequency dispersion. Excellent dielectric properties have been obtained for this composition. A value at 1 kHz reaches of about as 9700 was observed. The polarization versus electric field hysteresis measurements showed a well-defined hysteresis loop with a remanent polarization of 1.05 mu C/cm(2) with a coercive field of 0.85 kV/cm at room temperature. BaTi0.975(Zn1/3Nb2/3)(0.025)O-3 exhibits an important value of d(31) coefficient which reaches as high as-90 pCN(-1). From these results, we can consider this composition is of great interest for applications. (c) 2007 Elsevier B.V. All rights reserved.