Dielectric permittivity and electric modulus in Bi2Ti4O11

Frequency and temperature dependences of dielectric permittivity and electric modulus of pure and Ba-doped Bi2Ti4O11 were studied in the ranges of 10−1–106 Hz and −150–350 °C, respectively. We found that the antiferroelectric phase transition temperature of Bi2Ti4O11 decreases with Ba doping. In the permittivity studies, we also observed dielectric relaxation peaks shift to higher temperature with increasing frequency. Furthermore, in the electric modulus formalism, conducting peaks were uncovered above 150 °C in addition to the dielectric relaxation peak. We discussed the mechanisms for the dielectric relaxation and conduction processes based on TiO6 octahedra distortion and a space-charge model.