Effect of Pb substitution on the microstructure and ferroelectric properties of Ba_0.7Sr_0.3TiO₃ ceramic

Abstract

Ferroelectric Ba_0.7Sr_0.3TiO₃(BST) and partially Pb²⁺ substituted for Ba²⁺ ceramics (Ba_0.7−xPb _x)Sr_0.3TiO₃ (x=0.1–0.4, BPST) were prepared by using conventional solid-reaction method. XRD analysis shows that the samples microstructure changes from cubic phase to tetragonal one with the Pb²⁺ content increasing. ESEM analysis shows that the Pb²⁺ substituted samples have a denser and more uniform surface morphology than that of pure BST. Measured electrical properties suggest that the Pb²⁺ substitution for Ba²⁺ in the BST system enhances the ferroelectric performance obviously when x=0.2. In addition, the substitution increases the samples Curie temperature (T _c). (Ba_0.5Pb_0.2)Sr_0.3TiO₃ ceramic has good ferroelectric properties measured at a maximal electric field of 30 kV/cm under the condition of room temperature. The corresponding saturated polarization (P _s), remnant polarization (P _r) and coercive field (E _c) is respectively 15.687 μC/cm², 8.100 μC/cm² and 6.611 kV/cm. The measured T _c of (Ba_0.5Pb_0.2)Sr_0.3TiO₃ is 117 °C.

Keywords

Pb substitution / BPST ceramics / microstructure / ferroelectric properties

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