Aging of the linear and nonlinear dielectric susceptibility in a PLZT relaxor system

The aging of the linear and the third order nonlinear complex dielectric su sceptibility was investigated in the 9/65/35 PLZT ceramics by monitoring th e dielectric response as a function of the waiting time in an experiment us ing ac and dc measuring electric field. It was found that aging significant ly changes low frequency part of the relaxation spectrum of the linear comp lex dielectric constant. The static value of the dielectric constant follow s a power law for long waiting times. Also, it was shown that the third ord er nonlinear dielectric constant undergoes significant aging for long waiti ng times, however, it follows slightly different power law than the linear dielectric constant. The possible origin of the aging effects is discussed in terms of the pinning of the polarized nanoclusters.