Temperature dependent electrical transport behavior of (100-x)Bi2O3-x (BaTiO3) glass system

Impedance measurements were performed as a function of temperature (RT to 700 K) in the frequency range (1 Hz-1MHz) on fabricated Bismuth Barium Titanate glass samples. Dielectric permittivity is found to be increased on increasing both the temperature and BaTiO3 (BT) content in highly polarizable glass matrix of Bi2O3. Experimental data obtained for imaginary part of electric modulus (M)has been fitted theoretically using nonexponential Kohlrausch-Williams-Watts (KWW) function, however Jonscher's universal power law has been employed to analyze the frequency dependent ac conductivity. The calculated activation energy values for both the samples have been found to be in close agreement with each other and qualify for doubly ionized oxygen vacancies, proposing that the similar kind of charge carriers are involved in the relaxation and conduction mechanisms. Stretched exponent (beta) of Modulus and power exponent (n) of ac conductivity, estimated from theoretical fitting of experimental data, have been found to be dependent on temperature and BT (BaTiO3) content. On increasing temperature, an increase in values of (n) suggests that non-overlapping small polaron tunneling (NSPT) model can be easily applied to explain ac conduction and hopping transport mechanisms of the fabricated glass samples.

Automated summary

Experimental results show that increasing temperature and BaTiO3 content leads to an increase in dielectric permittivity of the glass matrix, with theoretical fitting models explaining the frequency-dependent behavior of electric modulus. The calculated activation energy values indicate the involvement of doubly ionized oxygen vacancies, while the increase in values of the power exponent suggests the application of non-overlapping small polaron tunneling model to explain the AC conductivity and hopping transport mechanisms of the fabricated glass samples.