Dual role of CoO and electron beam irradiation in enhancement the transport properties of borate glasses

Abstract

The synthesis of lithium borate cadmium glasses doped with cobalt oxide (CoO) (LiBCdCo) was achieved using the traditional melt-quench process. The chemical composition of the glasses was determined to be 12 % Li2O – 5 % CdO – (83-z)% B2O3, where z represents the mol% of CoO and ranges from 0.0 to 2. Various experimental approaches, such as X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, FTIR and electrical measurements, were employed to investigate the physical, structural, and electrical properties. XRD patterns obtained from the manufactured glass specimens revealed their amorphous nature. The EDX analysis provides insight into the exact chemical composition of the materials in their prepared form. Raman spectroscopy and FTIR analysis have been employed to verify the disparity in the chemical bonds present in lithium borate cadmium glasses, both in their undoped state and when doped with 2 % CoO. The study observed a decrease in density and oxygen packing density as the molar ratios of the modifier oxides in the produced glasses increased. The present study investigates the electrical conductivity and dielectric properties of the glass samples manufactured, focusing on the influence of electron beam irradiation (E.B.). The investigation revealed that the samples exhibited greater effects when exposed to higher doses (100 kGy) of electron beam irradiation. This can be attributed to the increased occurrence of defects, specifically the formation of non-bridging oxygen species (NBOs). The ac-conductivity measurements indicate that the correlated barrier hopping (CBH) mechanism is the most suitable explanation for the ac-conduction behavior observed. This mechanism involves the electron conduction in the CoO-doped glass samples through the hopping of electrons between relaxation sites. This conduction process is facilitated by the conversion of BO3 units into BO4 units and the reduction of cobalt ions from Co+2 to Co+3.