https://doi.org/10.1051/epjconf/201714005010
Electrical transport in granular metals
1 School of Civil Engineering, The University of Sydney, Sydney, Australia
2 Institute for Material Science and Technologies, Technische Universität Berlin, Germany
* Corresponding author: yixiang.gan@sydney.edu.au
Published online: 30 June 2017
In this paper, we studied the frequency-dependent AC conductance of randomly packed stainless steel spheres by means of impedance spectroscopy. Two types of power-law behaviour have been observed: (a) at low frequencies, the dependence of the measured impedance on the applied load; (b) at high frequencies, the dependence of the impedance modulus on frequency. Under different loading conditions, the imaginary parts of the measured conductances exhibit respective peaks at critical frequencies, corresponding to the onset of conductance dispersion. Using these critical points as scaling parameters to normalize the measured conductance, results in the spectra from different loading levels collapsing onto a single master curve. Both the electron tunnelling and capacitive paths among particles contribute to the conduction in granular metallic media, resulting in well-characterized universal behaviour.
© The Authors, published by EDP Sciences, 2017
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
