Annealing effects on the structural, positron annihilation parameters, and electrical properties of Fe₂O₃- PbO₂-TeO₂ glasses

Abstract

This study focuses on the transformation of selected glasses consisting of 20Fe2O3-(5+x) PbO2-(75-x)TeO2 (where x = 0, 5, 10, 15, and 20 mol%) with varying concentrations of PbO2, into nanomaterials through annealing at a temperature close to the crystallization temperature (Tc). The physical and chemical properties of the resulting samples were investigated. The chemical structure was analyzed using Fourier Transform Infrared spectroscopy (FTIR), which revealed no significant chemical changes except for an increase in the concentration of PbO2. X-ray diffraction (XRD) was used to study the crystal structure. Improvements were seen with increasing PbO2 concentrations, and these improvements were further increased after the sample was annealed. Furthermore, positron annihilation lifetime (PAL) spectroscopy was used to study the microstructure, more precisely the size of vacancy-type defects. A correlation was established between the PAL and the properties of the samples. The size of the vacancy-type defects was confirmed by calculating the distribution of the long lifetime deduced from the PAL. In this work, the overall influence of PbO2 concentration and thermal treatment on the chemical and crystalline structures, electrical conductivity, and microstructure of the studied nanomaterials is highlighted. The results provide valuable insights into the relationship between the PAL and the properties of the samples and provide potential opportunities to tailor their properties for different applications.