Influence of Bismuth Cations on the Synthesis and Ordering Behavior of Lead Magnesium Niobate and Barium Magnesium Niobate

摘要

The behavior of Bi~(3+) substituted on the A site of MMg_(1/3)Nb_(2/3)O_3 (M = Pb~(2+), Ba~(2+)) is shown to differ drastically from that of La~(3+). The more restricted isomorphism in the Bi-substituted systems compared to their La analogs is attributable to the fact that the bond strain in the Bi systems reaches the critical level. The lattice parameter of the Bi-substituted magnesium niobates is a very weak function of doping level, no 1 : 1 ordering occurs, their peak-permittivity temperature is a nonmonotonic function of Bi content, and their peak permittivity decreases with increasing Bi content, which is tentatively attributed to the incorporation of Bi in both A and B sites of the perovskite structure.