Percolation effects in mixed beta/beta ''-alumina crystals

Mixed beta/beta"-alumina crystals are two-dimensional ion conductors, whose conductivities vary dramatically upon mixing of two types of mobile ions. We summarize a theoretical model, which can explain these conductivity vari ations quantitatively. According to the model, percolation effects are expe cted to occur at intermediate mixing ratios and low temperatures. It is sug gested that detailed measurements should uncover these effects and thus all ow one to measure critical transport exponents predicted by percolation the ory. (C) 1999 Elsevier Science B.V. All rights reserved.