Scaling of AC electrical conductivity of
powders under compression
M.
Creyssels1, E. Falcon1,2
and B.
Castaing1
1 Laboratoire de Physique, Ecole Normale
Supérieure
de Lyon, CNRS, 69 007 Lyon, France
2 MSC, Université Paris Diderot - Paris 7, CNRS, 75
013 Paris, France
Reference:
Phys. Rev. B 77, 075135 (2008)
Abstract:
We measured, at low applied voltage, the AC
electrical resistance and capacitance of a metallic powder sample under
uniaxial compression. Whatever the applied stress, the frequency
dependent resistance curves can be displayed on a master curve by an
appropriated rescaling. The same property is also observed for the
capacitance. A one-dimensional model shows that the strong frequency
dependence of the macroscopic resistance and capacitance is a
consequence of the broad contact resistance distribution between
grains. No microscopic model of conduction nor any parameter related to
the unknown disorder need to be assumed. Relevance to other systems
like random conductor-insulator mixtures or metal-cluster compounds is
discussed.
PDF file
URL: http://link.aps.org/abstract/PRB/v77/e075135
doi:10.1103/PhysRevB.77.075135