Super slow polarization relaxation in PLZT relaxor ceramics

Using the method of continuous measuring of low- and infralow frequency dielectric response the features of super slow polarization relaxation processes in PLZT-8/65/35+0.1 Eu ceramics were investigated. It was shown that the time dependences of dielectric permittivity epsilon' may be described by approximation function of the type: epsilon'(t) similar to epsilon'(t o ) . exp[-ln(t/t o ) beta ] where t > t o and beta < 1. Also, the anomalies in temperature dependences of current i(T) in the short sample of non-poled and aged PLZT ceramics have been found. The obtained results are interpreted on the base of assumption that microelectrets (fractal clusters) appear with the course of time.