Dielectric, structural and specific heat properties of lead-free [(1-x)(Na_(0.5)Bi_(0.5))-xBa]Zr_(1-y)TiyO_3 ceramics (x = 0.06, 0.085, 0.09, 0.1 and y = 0.97)

摘要

Lead-free [(1-x)(Na_(0.5)Bi_(0.5))-xBa]Zr_(1-y)Ti_yO_3 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.