Dielectric, structural and specific heat properties of lead-free [(1−x)(Na_0.5Bi_0.5)−xBa]Zr_1−yTi_yO₃ ceramics (x = 0.06, 0.085, 0.09, 0.1 and y = 0.97)

Abstract

Lead-free [(1−x)(Na_0.5Bi_0.5)−xBa]Zr_1−yTi_yO₃ ceramics (x = 0.06, 0.085, 0.09, 0.1 and y = 0.97) have been prepared by solid-state hot-pressing sintering process. The obtained samples reveal perovskite structure. Structural, thermal expansion, heat capacity, ferroelectric and dielectric measurements have been carried out on these samples in a wide temperature range. The broad anomalies were observed in thermal expansion and heat capacity, which approximately correspond to a structural, ferroelectric and dielectric properties anomaly. These anomalies can be related to temperature features of polar regions and a formation of long-range-order ferroelectric phase. The determined Burns temperature was found to increase with increasing Ba content. The obtained results are discussed in terms of local electric and strain fields caused by a difference in the ionic radii of (Na,Bi) and Ba, and Ti and Zr ions. The NBT–BTZ system is expected to be a new promising candidate for lead-free electronic ceramics.

Keywords:

• NBT–BTZ system
• thermal properties
• structural properties
• dielectric properties