Relaxation dynamics in superionic molybdate glass nanocomposites embedded with α-AgI nanoparticles

Abstract

We have prepared silver molybdate glass nanocomposites of compositions xAgI-(1-x)(yAg₂O-(1-y)MoO₃) by melting the mixtures of the chemicals AgI, AgNO₃, and MoO₃ and quenching the melts. High-resolution transmission electron micrographs have been employed to detect the α-AgI nanoparticles present in the composites. We have studied relaxation dynamics of silver ions in these nanocomposites as a function of frequency and temperature. It has been observed that the variation of the average size of the α -AgI nanoparticles embedded in these nanocomposites and also the dilation of the glass network with AgI doping are responsible for the variation of the conductivity and hopping frequency with composition. The conductivity spectra have been analyzed using the power law model. We have observed that the power law exponent is almost independent of composition. The variation of the conductivity as well as the crossover frequency depends on the modifier to former ratio. We have estimated the concentration of mobile Ag⁺ ions from the Nernst-Einstein relation, which is found to be almost independent of temperature. We have further observed that only 20-23% of the total Ag⁺ ions contribute to the conduction process.