Dielectric Relaxation in Disordered Polar Dielectrics

A review of the current understanding of the effect of crystal lattice defects on the low-frequency dielectric relaxation properties in single crystals and polycrystalline polar dielectrics is given. Special attention is paid to different long-term phenomena, found in dielectric experiments, such as a low frequency relaxation polarization, a very slow relaxation of metastable states, a dielectric dispersion with a broad spectrum of distribution of relaxation times, a nonergodic behavior of the remanent polarization, etc. Mechanisms for dielectric loss and permittivity taking into account kinetics of defects rearrangement and their interactions in disordered inhomogeneous polar dielectrics are assessed.