Structure and electric conduction of Fe2O3-P2O5 glasses

IR spectroscopy, density and DC conductivity measurements have been carried out for Fe2O3-P2O5 glasses. Results indicate that the redox ratio of the Fe2+ ions decreases while the density increases with increasing Fe2O3 content. It is suggested that the change of density might be correlated with the change in the relative concentration of FeO4 and FeO6 units. Analysis of the IR spectra reveals that Fe2O3 enters the phosphate matrix in the form of Fe2+ and Fe3+ ions through the formation of P-O-Fe2+ and P-O-Fe3+ bonds at the expense of P-O-P bonds. The conductivity data were analyzed in terms of Mott's model for small polaron hopping. Variation in conductivity is correlated with structural changes that take place upon increasing the Fe2O3 content in the glasses. (C) 2004 Elsevier B.V. All rights reserved.