材料期刊网

The DC and AC hopping conduction in some fractal systems are studied. The DC conductivity is analysed in some partial fractal systems where both localized and superlocalized states exist. The AC conductivity sigma(omega) is shown to scale as omega[ln(nu(ph)/omega)]((D+2-zeta))/(zeta) and is proportional approximately to omega(s) with s = 0.88 for three-dimensional percolation. The ambiguities in the analysis of conductivity data are discussed and it is pointed out that the measurement of some characteristic length scales is very important in analysing the hopping mechanism and the origin of localization from experimental results.