Dielectric relaxation in ferroelectrics

Ferroelectrics are important multifunctional materials with applications ranging from high E_r capacitors to non-volatile memory devices. Dielectric relaxation studies of ferroelectrics help elucidate the various mechanisms responsible for polarization. These insights are beneficial for materials engineering and tailoring of specific properties. In the present review, a comparison among the paraelectric, ferroelectric and physical states of the material are made. Compositional and dopant effects are also addressed. In ferroelectrics, the domain structure is shown to play a crucial role in determining both the nature and mechanism of the dielectric relaxation in the microwave region. At lower frequencies interfacial polarization dominates, especially for polycrystalline samples.