Hydrogen-induced percolation in discontinuous films

Abstract

Hydrogen absorption in a metal leads to significant lattice expansion. This effect can be applied for discontinuous films to make them exceed the percolation limit, turning the film from nonconducting to conducting. Furthermore, in a percolating system, the conductivity should depend strongly on the external hydrogen pressure. This letter discusses the idea of a hydrogen-induced percolation mechanism. The process is illustrated by measurements on agglomerated palladium films, showing a maximum decrease of the resistivity by 50% at an exposure of the films to 5x10(4) to 9x10(4) Pa. The agglomerated films are prepared by Joule heating, using heat dissipation in the film itself. (C) 2002 American Institute of Physics.