Fractal analysis of anomalous low-frequency dispersion in X2BaCuO5 compounds (X=La-Y)

The anomalous low-frequency dispersion process observed in perovskite ceram ics (X2BaCuO5,X = La-Y) is described by a fractal model. The interpretation is given in terms of the Dissado-Hill-Jonscher theory and is based on a cl uster description of the structural ordering and fluctuation in carrier-dom inated dielectrics. The relationship of the mechanism to that of power-law noise in electrical systems is identified and its dynamical and structural interpretation explored. Particular features of several ceramics related to superconductor compounds are described. [S0163-1829(99)09931-2].