Structural and magnetic investigations on gadolinium-tellurite vitreous systems prepared by sol-gel method

In this study, we report structural investigations on gadolinium-tellurite systems obtained by sol-gel method. The samples were characterized by X-ray diffraction, DSC, FTIR, UV-VIS and EPR spectroscopy. FTIR results have shown the partial transformation of six-coordinated tellurium (VI) from [TeO6] structural units in four-coordinated tellurium (IV) by addition of Gd(NO3)(3) content. Also, the addition of Gd(NO3)(3) to tellurite matrix favorites the formations of [TeO3] and [TeO4] structural units. Optical absorption spectra of the gadolinium nitrate doped tellurite systems consist in a series of narrow bands which can be ascribed to the 4f-4f intra-configurational transitions of the Gd3+ ions between S-8 ground state and P-6(J), I-6(J) and D-6(J) multiplets. The EPR spectra of Gd3+ ions in gadolinium-tellurite system exhibit two broad EPR signals at g similar to 2.0 and g similar to 6. (C) 2012 Elsevier B.V. All rights reserved.