Published online by Cambridge University Press: 10 February 2011
Two techniques for measurement of local electrical conductivity of inhomogeneous materials are described. I) A novel variant of the impedance technique for thin/thick film characterization was developed; due to the two-dimensionality of the cell set up, at different frequencies different parts of the material are probed. The technique was experimentally verified by measuring the position coordinate of a Ag strip artificially added to a AgCl film. Its application to the Ag/AgCl boundary is touched upon. II) Micro-electrodes were used to probe surface conductances and local subsurface conductivities. The technique was implemented by a home-made high impedance adapter and combined with AFM to measure the contact area. Several examples of application are shown, viz. measurements of a) the enhanced surface conductivity of mechanically polished AgCl crystals, b) the interdiffusion coefficient of Cd2+ in AgCl, and c) the grain conductivity of polycrystalline AgCl.