抄録
The 57Fe Mössbauer spectra of xLi2O·2FeO·V2O5·P2O5 and xNa2O·2FeO·V2O5·P2O5 glasses (x = 0, 0.5, 1.0 and 1.5) consist of two doublets due to FeII and FeIII. The isomer shift indicates that FeIII atoms form FeIIIO4 tetrahedra or FeIIIO6 octahedra, while FeII atoms from FeIIO6 octahedra. A liner relationship exists between the glass transition temperature, Tg, and the quadrupole splitting, Δ, of FeIII atoms in the Mössbauer spectra. Slopes of the straight lines were estimated to be 460 and 370°C (mm s-1)-1 in xLi2O·2FeO·V2O5·P2O5 and xNa2O·2FeO·V2O5·P2O5 glasses, respectively. These results suggest that FeIII atoms form oxygenpolyhedra that are intermediate between FeIIIO4 tetrahedra and FeIIIO6 octahedra. The electric conductivity obtained by a dc four-probe method was of the order of 10-5 to 10-6 S cm-1.
