Investigation of dielectric aging in layered ferroelectrics

The specific features of long-term relaxation of the polarization in the Na 0.5 Bi 8.5 Ti 2 Nb 4 O 27 and Na 0.5 Bi 8.5 Ti 2 Ta 4 O 27 ceramic materials with different prehistories are investigated. It is established that, for the Na 0.5 Bi 8.5 Ti 2 Nb 4 O 27 and Na 0.5 Bi 8.5 Ti 2 Ta 4 O 27 ceramic materials, a change in the measurement conditions, including heating or cooling to the temperature T a under investigation, leads to a change in the time dependence ε ′( t ) describing the dielectric aging of the material at T a = const. The results obtained are discussed from the viewpoint of the possible existence of defect complexes in disordered ferroelectrics.