Wide Range Dielectric Spectroscopy of Barium Strontium Titanate Ceramics.

摘要

Wide band dielectric spectroscopy was applied from kHz to THz region for the analysis of both the ionic and the dipole polarization in Ba_(0.6)Sr_(0.4)TiO_3 ceramics. The dielectric permittivity above the dielectric maximum temperature (T_m) is mostly dominated by the ionic polarization, while that below T_m is governed by the dipole polarization. Dielectric permittivity given by the dipole polarization increased and the relaxation frequency decreased with decreasing temperature. These phenomena are related to a increase of the size of polar nanoregions (PNRs).