Ultrawideband dielectric spectroscopy of BaZr_xTi _1-xO₃ ceramics and its microscopic mechanism of polarization

Ultrawideband dielectric spectroscopy analysis of barium zirconate titanate (BaZr_xTi_1-xO₃BZT) ceramics at different temperatures disclosed the contribution of both the dipole and the ionic polarizations to permittivity at around dielectric maximum temperature (T _m). In BaZr_0.25Ti_0.75O₃ ceramics, the permittivity around T_m is dominated by the temperature dependence of the permittivity determined by the dipole polarization (εdipole). In relaxor ferroelectrics, the diffuse dielectric response around T_m could be derived from the temperature dependence of εdipole. The variation of εdipole with temperature could be also explained by the growth process of polar nanoregions (PNRs) and the damping process of the thermal fluctuation of dipoles in PNRs.