Fe2O3-induced crystallization and the physical properties of lead arsenate glass system

PbO-As2O3 glasses mixed with different concentrations of Fe2O3 (ranging from 0 to 2.0 mol%) were crystallized. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) techniques. Studies were extended to optical absorption, IR, ESR and magnetic susceptibility on these glass ceramic samples. The X-ray diffraction and scanning electron microscopic studies reveal the presence of PbFe4(As5O11)2, Fe2PbAs2O6 crystal phases. The optical absorption studies together with ESR and magnetic susceptibility measurements indicated the dominant presence of iron ions in the trivalent state when the concentration of nucleating agent Fe2O3 is less than 0.3 mol%. The analysis of the IR spectra indicated a gradual transformation of iron ions from tetrahedral sites to octahedral sites as the concentration of Fe2O3 is increased beyond 0.3 mol%.