ELECTRICAL-PROPERTIES OF SEMICONDUCTING BARIUM VANADATE GLASSES CONTAINING IRON-OXIDE

Electrical conductivity, molar volume and microhardness measurements o f some semiconducting barium vanadate glasses doped with iron were car ried out and studied. The conduction mechanism is found to be due to s mall polaron hopping between the different valence states of vanadium ions only and is of nonadiabatic type in its nature. The results showe d that the conductivity of the studied glasses does not depend solely on polaron radius and on redox ratio V4+ l (V4+ + V5+) but the network structure plays an important role in affecting the electrical paramet ers. An inflection in the graphs for molar volume, microhardness and e lectrical conductivity at 5 mol% of Fe2O3 content was observed and exp lained on the basis of the structure modification which accompanied th e addition of iron.