Frequency-temperature response of Ba0.97La0.02Ti0.95Nb0.04O3 ceramic prepared by molten-salt method: impedance and modulus spectroscopy characterization

The chemical molten-salt process was used for the elaboration of a new polycrystalline perovskite compound of Ba0.97La0.02Ti0.95Nb0.04O3 (shortened in BLT0.95Nb0.04). Analysis of XRD patterns using Rietveld refinement reveals that the prepared sample crystallizes in single phase form, with a tetragonal structure, with a P4/mmm space group. Then, a simultaneous investigation of impedance and modulus was effectuated. Complex impedance plots confirm the existence of semicircular arcs which expressed by an electrical equivalent circuit to clarify the impedance consequences. Off-centered semicircular impedance plots makes obvious that the synthesis sample conforms to a non-Debye relaxation manner. Furthermore, it is typically controlled by thermally activated charge carriers. The reducing of resistance, with rising temperature (T), indicates a negative temperature coefficient of resistance, which highlighting that the relaxation process is dominated by the inter-grains.