FREQUENCY-RESPONSE ANALYSIS OF THE FAST-ION CONDUCTING SYSTEM CUPROUSIODIDE SILVER CHROMATE

Preparation and characterization of new superionic conductors have bee n considered to be an 'essential component in the area of solid state ionics. The details of frequency response analysis carried out in term s of impedance (Z), conductivity (sigma) and modulus(M) diagrams on a series of compositions in the mixed system CuI-Ag2CrO4 exhibiting Agionic conductivity over the temperature-range 290-400 K and in the fre quency range 65.5 kHz-1Hz are presented in this paper. The frequency - dependent conductivity spectra have been found to obey the Jonscher's power law over the temperature range under investigation. The observe d temperature dependence of conductivity has indicated that a low acti vation energy is associated with the composition possessing high condu ctivity and vice versa. The separation of grain - boundary and electro de polarisations from the bulk impedances has been made feasible throu gh the impedance spectra. A long tail in the low-frequency region and a tendency to peak at higher frequencies in the modulus diagram have s hown that it is possible to effectively suppress the information conce rning grain-boundary and electrode effects in the modulus formalism. M odulus and impedance spectra have indicated the non-Debye type of pola risation in the above material.