Aging of CKN: Modulus versus conductivity analysis

TL;DR

This paper compares modulus and conductivity analyses of aging in CKN, revealing that while modulus peaks narrow with annealing, conductivity shape remains unchanged, supporting the random barrier model.

Contribution

It clarifies the relationship between modulus and conductivity analyses during aging and confirms the applicability of the RBM to CKN.

Findings

Modulus peaks narrow upon annealing.

Conductivity shape remains unchanged during aging.

Conductivity conforms to the random barrier model.

Abstract

It was recently reported that the electrical modulus peaks narrows upon annealing of the ionic system CKN [Paluch et al., Phys. Rev. Lett. 110, 015702 (2013)], which was interpreted as providing evidence of dynamic heterogeneity of this glass-forming liquid. An analysis of the same data in terms of the ac conductivity shows no shape changes, however. We discuss the relation between both findings and show further that the ac conductivity conforms to the prediction of the random barrier model (RBM) at all times during the annealing.