EPR study of Gd3+ doped lead oxide based glasses

The electron paramagnetic resonance (EPR) spectra of Gd3+ ions in lead germanate and lead phosphate glasses are analyzed as a function of Gd content and host composition in the temperature range between 4.2 and 300 K. The investigated samples were (40-x)PbO . 60GeO(2) . xGd(2)O(3) (x = 0.25, 0.5, 1, 2, 3, 4 mol %) and 97.5Pb(PO3)(2) . 2.5Gd(PO3)(3) glasses, prepared by conventional melting technique. From comparison of spectra on different samples-some of which partially crystallized-no evidence emerges of the existence of distinct types of Gd3+ coordination environments. The analysis of the line-broadening by increasing the Gd3+ content evidences that the line width of the EPR signal components is proportional to the concentration of rare earth ions, suggesting that clustering effects are negligible, at least up to 4 mol % Gd2O3. (C) 1999 Kluwer Academic Publishers.