EPR and FT-IR spectroscopic studies of Bi2O3-B2O3-CuO glasses

EPR and FT-IR absorption measurements have been performed for xCuO center dot (100-x)[2Bi(2)O(3) center dot B2O3] glass system, with O <= x <= 50 mol%. The mode in which the addition of the copper ions influences the structure of 2Bi(2)O(3) center dot B2O3 glass matrix was analyzed. The EPR absorption spectra revealed the presence in the glass structure of Cu2+ ions in axially distorted octahedral environments. EPR data pointed out the simultaneous presence of Cu2+ and Cu+ ionic species in the glasses with x >= 5mol%. For x > 10 mol%, the Cu2+ ions participate in the superexchange magnetic interactions, which increase with CuO content. The FT-IR spectra showed the presence of some bands that are assigned to vibrations of Bi-O bonds from BiO3 pyramidal and BiO6 octahedral units and B-O bonds from BO3 and BO4 units. The data obtained by these measurements reveal the structural changes in the 2Bi(2)O(3) center dot B2O3 glass matrix by controlled doping of CuO. (C) 2008 Elsevier B.V. All rights reserved.