Spectroscopic properties, conduction processes and the Summerfield scaling of barium titanate ceramics based on Bi and Fe

In this study, the effects of Bi and Fe on the optical and electrical qualities of BaTiO3 made with the sol-gel method are examined. On the one hand, UV-visible spectroscopy is used to study the sample's optical behavior. This shows that the band gap energy is lower with Bi and Fe doping than with pure BaTiO3. On the other hand, an impedance spectroscopy investigation is carried out to reveal the conduction processes in the frequency range of 102 to 107 Hz and the temperature range of 450-650 K. This examination is carried out to investigate the conduction mechanisms. The conduction mechanism in the elaborated material is best described by the Overlapping Large Polaron Tunnelling model (OLPT), where the exponent s drops with temperature until reaching a minimal value, at which point it grows again. In addition, the Summerfield scaling method is used to investigate the relationship between conductivity and temperature. When the scaled curves are combined into one master curve, it shows that the time-temperature superposition principle (TTSP) is true and that Koop's concept about how the dielectric constant change with frequency is valid. So, the results give us new information about the optical and dielectric qualities of the functional barium titanate ceramics based on Bi and Fe.