Relaxor behavior of La-modified (Pb0.75Ba0.25)(Zr0.70Ti0.30)O3 ceramics

Abstract

Strong influence of the lanthanum (La) admixture added to the lead–barium–zirconate–titanate (PBZT) ceramics of a chosen composition (Ba/Zr/Ti-25/70/30) on grain structure, electric conductivity, as well as dielectric and pyroelectric properties was confirmed. The La-modified ceramics exhibit classical relaxor ferroelectric behavior similar to other complex lead perovskites such as lead–lanthanum–zirconate–titanate-type ceramics. Additional anomalies in ε(T) curves in low frequency range were observed in the paraelectric phase for undoped ceramics. These anomalies and some disturbances in regularities typical for the relaxor ferroelectric behavior in the vicinity of diffuse ferroelectric–paraelectric phase transition in undoped PBZT ceramics are eliminated by the La admixture, which reduces the p-type electric conductivity by three orders of magnitude. An attempt at a qualitative explanation is given in the article.