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Raman and EPR investigation of some lead-phosphate glasses with vanadium and copper ions

N. VEDEANU1,* , O. COZAR1, I. ARDELEAN1, V. IONCU1

Affiliation

  1. Faculty of Physiscs, Babes-Bolyai University, 400084 Cluj-Napoca, Romania

Abstract

x(CuO•2V2O5)(1-x)[2P2O5•PbO] glass system with 0 ≤ x ≤ 40 mol% was investigated by EPR and Raman spectroscopy in order to see the structural changes induced by both copper and vanadium ions in different ratios and their modifier or former role. EPR spectra and parameters (g║ = 2.44, g┴ = 2.08 and A║ = 117.6•10-4 cm-1) obtained for the studied glasses with x≤10 mol% suggest a tetrahedral (Td) coordination of Cu2+ ions and not a tetragonally elongated octahedron as has been assumed in previous works. The resonance parameters for V4+ suggest a pentacoordinated C4v local symmetry for them. The hyperfine structures characteristic for Cu2+ and V4+ ions disappear for 10≤x≤40 mol% due to the mixed exchange Cu2+-V4+ pair formation in these glasses. Raman spectra of the studied glass system show for low concentration of ions the specific bands belonging to the phosphate groups, but at high concentration of V4+ (x ≥20 mol%) the bands belonging to the vibration of V2O5 groups dominates the spectra. In the same time the bands belonging to the phosphate groups are strongly reduced except the specific bands of the short chain phosphate units. This suggest that in the studied glasses vanadium acts as a network former at high concentration of V2O5..

Keywords

Lead-phosphate glass, Vanadium addition, Chromium addition, Raman spectroscopy, EPR.

Submitted at: Nov. 2, 2006
Accepted at: April 15, 2007

Citation

N. VEDEANU, O. COZAR, I. ARDELEAN, V. IONCU, Raman and EPR investigation of some lead-phosphate glasses with vanadium and copper ions, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 4, pp. 844-847 (2007)