The Nature of Dielectric Nonlinearity in the Region of Diffused Phase Transition in Layered Ferroelectric BaBi_2Nb_2O_9

摘要

By studying the dielectric properties of BaBi_2Nb_2O_9 ceramics, a representative of layered ferroelectrics, significant dispersion of epsilon* has been revealed at low- and infra-low frequences in the region of phase transition. Dispersion of epsilon* observed in "low-temperature" region (T < T_m) is caused by relaxation of polar formations and their borders. The "high-temperature" dispersion is observed in the region T > T_m where the basic contribution to epsilon* is provided by processes of the Maxwell-Wagner relaxation.