Impedance spectroscopy analysis of an FeNbO4 matrix with different additions of TiO2 and the effects of temperature variation

Abstract

In this work, investigations of the FeNbO4 ceramic matrix (FNO) and TiO2 additions were carried out in 0, 20, 40, 60, and 80% wt. proportions. The material was synthesized using the solid-state reaction method in an energy mill, and the phases were confirmed by X-ray diffraction and Rietveld refinement. The study of complex electrical impedance was carried out using real and imaginary impedance, with measurements such as permittivity, conductivity, activation energy, and complex impedance diagrams in the range from 1 Hz to 1 MHz and with temperature variation from 100 to 300 oC using a Solartron 1260 impedance analyzer. Furthermore, the temperature coefficients of capacitance for the FNO matrix and its additions were also studied. The complex impedance diagrams showed a non-Debye type relaxation, where the adjustments made showed a good relationship between the experimental and simulated results, and the conduction process was thermally activated, following the Arrhenius relation, where the activation energies calculated were 0.46 and 0.53 eV for the FNO sample, calculated by the displacement of the maximum impedance peak and by the conductivity with temperature variation at 1 Hz. The results showed a greater understanding of the conduction processes of the FNO-TiO2 composite.