Structural and electric-dielectric properties of some bismuth -phosphate glasses Original Research Article

In the present study, glasses with composition XBi2O3 (60−X)P2O5 20Fe3O4 20Li2O (0≤X≤15) mol% have been prepared by the conventional melt quenching technique. The IR studies show the presence of FeO4, FeO6, BiO6, PO3, PO and PO4 structural groups. The hyperfine structure of these glasses is investigated using Mössbauer spectroscopy. ME spectroscopy indicated the presence of two different oxidation states of iron (Fe2+ and Fe3+). The ferrous ions Fe2+ occupied tetrahedral coordination states, while the ferric ions Fe3+ occupied both tetrahedral and octahedral coordination states. The effect of partial replacement of P2O5 by Bi2O3 on the electric-dielectric properties is studied in more details. It is found that, unmonotonic variation in the σdc, (θD/2), σac(ω), ε1(ω), and ε2(ω), as a function of Bi2O3 contents. Also it is found that, the power law exponent, s, is temperature dependent and the CBH model is the most applicable conduction mechanism in all glass samples. Pseudo Cole-Cole diagram of the investigated glassy samples exhibit similar behavior where all plots show a single semicircle indicating a single relaxation process.