Structural and optical properties in gadolinium–aluminum–lead-germanate quaternary glasses

• Published in: Journal of non-crystalline solids 2011-04, Vol.357 (7), p.1724-1728
• Main Authors: Rada, S., Culea, E.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Disordered solids; Exact sciences and technology; FTIR and UV–VIS spectroscopy; Gadolinium–aluminum–lead-germanate glasses; Gd 2Ge 2O 7 crystalline phase; Glasses; Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics; Structure of solids and liquids; crystallography
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2011.01.017

Glasses in the quaternary system 0.05Al 2O 3·0.95[xGd 2O 3·(100-x)(7GeO 2·3PbO)] with 0 ≤ x ≤ 40 mol% have been prepared from melt quenching method. In this paper, we investigated structural and optical properties in gadolinium–alumino–lead-germanate glasses through investigations of FTIR (Fourier-Transform Infrared Spectroscopy) and UV–VIS (Ultra-Violet) spectroscopy. The observations presented in these mechanisms show that by increasing Gd 2O 3 content up to 40 mol%, the glass network modification has taken place mainly in the germanate part, while the excess of oxygen can be accommodated in the host network by the creation of shorter rings of [Ge 2O 7] structural units and the formation of [AlO 4] structural units. The affinity pronounced of the gadolinium cations towards germanate structural units produces the formation of the Gd 2Ge 2O 7 crystalline phase. The UV–VIS spectroscopy data show the charge transfer transitions of Pb + 2 –O − 2 , Al + 3 –O − 2 and Gd + 3 –O − 2 , respectively. The additional absorption in the range of 300 to 600 nm was attributed to other types of defects such as: non-bridging oxygen ions, change in valency of ions and other color centers. The values of the direct optical band gap of the glasses are determined from the optical absorption spectra. By increasing Gd 2O 3 content in the glass matrix, the optical band gap energy increases indicating changes of the lattice parameters by Gd 2O 3 incorporation. ► 0.05Al 2O 3·0.95[xGd 2O 3·(100-x)(7GeO 2·3PbO)] glasses. ► Gd 2Ge 2O 7 crystalline phase. ► FTIR and UV -VIS spectroscopy.