Impedance spectroscopy investigations on the electrical response and morphology of BiBaFeTiO6 double perovskite for multifunctional applications

Abstract

BiBaFeTiO₆ was synthesized successfully through a sol–gel method. XRD examinations revealed that the compound exhibited a crystalline cubic double-perovskite structure with the space group Pmm. The morphology and elemental composition were examined using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and elemental mapping. Results revealed that the material had a uniform distribution of elements and the predicted chemical composition. Electrical measurements were conducted in the temperature range of 373–453 K and the frequency range of 0.1 Hz to 1 MHz. The AC conductivity of BiBaFeTiO₆ was established using the correlated barrier hopping (CBH) model. Activation energies derived from DC conductivity and modulus spectra were comparable, indicating that both the relaxation process and electrical conduction originated from the same underlying mechanism. Furthermore, a thorough examination of the Nyquist plots showed the sensitivity of the material's electrical properties to changes in temperature and frequency. The sample's semiconducting nature was demonstrated by the resistivity and impedance NTCR (negative temperature coefficient of resistance) properties. The Nyquist plots (−Z″ vs. Z′) display the contribution of grains and grain boundaries in the electrical conductivity, confirming the existence of a non-Debye-type relaxation. The non-overlapping small polaron tunneling (NSPT) process in BiBaFeTiO₆ is suggested by the value of the exponent “s”, which denotes the conduction process described by the Correlated Barrier Hopping (CBH) model. This material's NTCR characteristics, including a good stability factor, thermistor constant, and sensitivity factor, may be beneficial for developing NTC-type thermistors.