Релаксационные процессы в области структурных фазовых переходов на примере керамики на основе ниобата натрия

Abstract

Comparative studies of the temperature dependences and dispersion of the complex permittivity of sodium niobate and sodium-lithium niobate ceramics have been carried out. It is shown that the structural transition to the R phase (370°C) of sodium niobate ceramics is a ferroelectric phase transition. For sodium niobate ceramics, the existence of three fundamentally different mechanisms of relaxation processes has been established: classical (Debye type), linear, and relaxation (elastic ionic), the existence of which is determined by the structural phase. The addition of 10% lithium niobate to the sodium niobate ceramics not only increases the temperature of the structural phase transition, but also eliminates the mechanisms for the occurrence of relaxation polarization.