Relaxor behavior of La-modified (Pb0.75Ba0.25)(Zr0.70Ti0.30)O-3 ceramics

Strong influence of the lanthanum (La) admixture added to the lead-barium-z irconate-titanate (PBZT) ceramics of a chosen composition (Ba/Zr/Ti-25/70/3 0) on grain structure, electric conductivity, as well as dielectric and pyr oelectric properties was confirmed. The La-modified ceramics exhibit classi cal relaxor ferroelectric behavior similar to other complex lead perovskite s such as lead-lanthanum-zirconate-titanate-type ceramics. Additional anoma lies in epsilon (T) curves in low frequency range were observed in the para electric phase for undoped ceramics. These anomalies and some disturbances in regularities typical for the relaxor ferroelectric behavior in the vicin ity of diffuse ferroelectric-paraelectric phase transition in undoped PBZT ceramics are eliminated by the La admixture, which reduces the p-type elect ric conductivity by three orders of magnitude. An attempt at a qualitative explanation is given in the article. (C) 2001 American Institute of Physics .