Polarization anomalies in a relaxor ferroelectric

With a strontium barium niobate crystal used as an example, it is experimen tally demonstrated that relaxor ferroelectrics exhibit pronounced polarizat ion anomalies, which manifest themselves in the difference between the traj ectories of the dielectric hysteresis observed in several repeated cycles o f a varying external electric field. These anomalies originate from the non uniformity of the relaxor composition, local symmetry lowering, local inter nal electric field, and a wide distribution of potential barriers in energy for the polarized regions. The anomalies can be observed only in slowly va rying (quasistatic) or constant electric fields. (C) 2000 MAIK "Nauka/Inter periodica".