In the measurements, use was made of model films 15a Nm in thickness, with the conductive component of Bi2Ru2O7 dispersed in glass having the composition 66 % PbO + 32 % SiO + 1.5 % Al2O3. The courses of the voltage dependence of resistivity are interpreted as the Poole-Frenkel phenomenon on isolated admixture centres in glass. The measurement on the isolated admixture centres was made possible by selecting samples having the concentration of the conductive component closely below the critical concentration (the percolation limit). As predicted, the charge transport proceeded by the hopping mechanism in the empty zone of delocalized states, which, according to an analysis of the results, lies by 0.76a0,05 eV above the narrow impurity band [3,10].
