Influence of dc bias electric field on Vogel-Fulcher dynamics in relaxor ferroelectrics

摘要

Changes in dynamic processes of relaxors due to a dc bias electric field have been studied in the reduced poly(vinylidene fluoride-trifluoroethylene), a copolymer system where relaxor-like behavior in the crystalline part can be separated from the glassy processes in the amorphous matrix. Strong electric field dependence of the Vogel-Fulcher temperature and the activation energy has been detected. Comparison of the results with those obtained in a classical inorganic relaxor, lanthanum-modified lead zirconate titanate ceramics, reveals that the nonlinear dielectric susceptibility dominantly influences the dielectric dynamics of relaxors in dc bias electric fields. We have additionally found that even low bias voltage effectively blocks the ac electrical conductivity of the studied copolymer.