Experimental and theoretical study of AC electrical conduction mechanisms by NSPT model of LiNaAgPO ( x = 0.2 and 0.6) ceramic compounds.

New pyrophosphate of ceramic compounds LiNaAgPO ( x = 0.2 and 0.6) is synthesized by a solid-state method. All the compounds crystallize in the orthorhombic lattice with space group C222. The infrared spectra of these compounds show characteristic bands due to a PO group. The two semicircles observed in the complex impedance identify the presence of the grain interior and grain boundary contributions to the electrical response in these materials. The frequency independent conductivity of these compounds shows Arrhenius-type behavior. The activation energies have been calculated at the levels of impedance, electric modulus studies, and DC conductivity which suggest that the conductions are ionic in nature. The conductivity increases with an increase in Ag substitution. In order to determine the conduction mechanism, the AC conductivity and its frequency exponent have been analyzed in this work by a theoretical model based on quantum mechanical tunneling: the non-overlapping small polaron tunneling model (NSPT) is confirmed for x = 0.2 and x = 0.6. The conduction mechanism is studied with the help of Elliot's theory, and the Elliot's parameters are determined. [ABSTRACT FROM AUTHOR]