Investigation on relaxation properties of deep bulk trap in CaCu₃Ti₄O₁₂ ceramics

The relaxation properties of deep bulk trap in CaCu₃Ti₄O₁₂ ceramics prepared by solid state reaction and coprecipitation method were investigated. Dielectric spectra at frequency from 0.1 Hz to 10⁷ Hz and in the temperature range from -100°C to 100°C were measured. With the analysis of dielectric spectra at different temperature, deep bulk trap relaxation in double Schottky barrier was studied. The relative position between deep bulk trap and Fermi level changed in double Schottky barrier under small AC signal, resulted in electron emission and capture of deep bulk trap, namely relaxation, which exhibited as a peak in dielectric frequency spectra. Furthermore deep bulk trap level, can be received based on frequency spectra analysis. Compared with the parameters of different samples, it is found that there exist deep bulk traps caused by interior defect at the levels with 0.52 eV and 0.12 eV lower than conduction band. The analysis of dielectric temperature spectra is similar, which can be complement for dielectric frequence spectra analysis.