Spectroscopic and magnetic behaviour of xGd2O3 (1-x)(Bi2O3 •PbO) glasses

Glasses of the xGd(2)O(3) (1 - x)(Bi2O3.PbO) system (0 less than or equal to x less than or equal to 0.15) were obtained and studied by IR spectroscopy, electron paramagnetic resonance (EPR), magnetic susceptibility and density measurements. IR data show that increasing the amount of gadolinium ions in the studied glasses produces structural modifications of the host vitreous matrix consisting in a conversion of the [BiO3] into [BiO6] structural units. EPR and magnetic susceptibility data show that for low gadolinium oxide content of the samples, x less than or equal to 0.05, the Gd3+ ions are randomly distributed in the host glass matrix and are present only as isolated species. For higher gadolinium oxide contents of the samples, x > 0.05, the Gd3+ ions appear as both isolated and antiferromagnetically coupled species. IR and density measurements support the assumption of the network modifier role played by the gadolinium ions in the xGd(2)O(3) (1 - x)(Bi2O3.PbO) glasses. EPR data show an unusual absorption line for the Gd3+ ions in glass matrices. This absorption line is due to Gd3+ ions that replace Bi3+ and Pb4+ ions from the host glass matrix and play the network former role in the studied glasses. (C) 2004 Elsevier B.V. All rights reserved.