Ferroelectric Na_(0.5)Bi_(0.5)TiO_3 and K_(0.5)Bi_(0.5)TiO_3 Perovskites and Their Solid Solutions

摘要

Properties of the perovskiteferroelectrics Na_(0.5)Bi_(0.5)TiO_3 (NBT), K_(0.5)Bi_(0.5)TiO_3 (KBT) and their solid solutions are reviewed. Consideration of the NBT behavior draws attention to phenomena of the ion ordering, coexistence of several phase regions within a crystal lattice, phase transition diffusion and to a quite new phenomenon: existence of the isotropization points (temperatures) in the AFE-phase-temperature interval. In the KBT the isotropic points are absent. NBT, KBT, and their solid solutions are considered as possible useful materials for technical (in particular, for piezoelectric) applications. There are also some other A_(0.5)~+Bi_(0.5)B~(4+)O_3 perovskites which are interesting for future research.