Broadband Dielectric Spectroscopy Analysis of Dielectric Properties of Barium Titanate Ceramics

摘要

The complex dielectric behaviors of ferroelectric barium titanate (BT) ceramics were investigated. The dielectric properties were studied as a function of temperature and frequency using broadband dielectric spectrometer. The results show that the maximum value of dielectric constant occurs at 500nm BT ceramics, which is approximately 7,500; the dielectric loss is lower than 0.03 with the temperature varying from 225 K to 450 K. Dielectric constant and dielectric loss experience three dielectric peaks corresponding to rhombohedral to orthorhombic, tetragonal and cubic transitions. With the frequency ranges from 1 MHz to 1 GHz, the dielectric relaxation is apparently present. The relaxation process obeys Cole-Cole relaxation model at high temperature and conforms to Debye relaxation model with the temperature far lower than Curie temperature. The relaxation time is the order magnitude of ~10-9 s obtained by Havriliak-Negami function fitting, which is very consistent with theoretical calculation.