Structure and EPR investigations on Gd³⁺ ions in magnesium-lead-borophosphate glasses

Gadolinium (Gd3+)-doped magnesium-lead-borophosphate glasses composed of MgHPO4-PbO-B2O3-Gd2O3 (PPbBMgGd) were fabricated by usual melt-quenching approach. The physical properties such as refractive index (n), density (rho) and molar volume (V-m) were attained. Thermal analysis of the glass has been performed through differential scanning calorimetry (DSC). Raman, Fourier transform infrared (FTIR), Electron Paramagnetic Resonance (EPR) and steady-state luminescence of PPbBMgGd glasses were investigated. The Raman and FTIR spectra explore the vibrational groups of both phosphate and borate networks in the PPbBMgGd glasses. The EPR spectra display three characteristic signals at room temperature with definite g values of 6.2, 2.8 and 2.0. These characteristic signals were ascribed perhaps the Gd3+ ions that are located respectively at feeble, moderate and sturdy cubic symmetry sites. Moreover, the EPR spectra were also obtained at various low temperatures (123-297 K) for 5.0 mol% of Gd3+-doped PPbBMgGd5.0 glass. Difference in population among the Zeeman levels (N) and paramagnetic susceptibility (chi) were evaluated. Photoluminescence spectrum reveals a broad intense band of Gd3+ ions upon excitation at 278 nm, could be suitable for visible broadband applications. (C) 2020 Elsevier B.V. All rights reserved.