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 8S ground state and 6PJ, 6IJ and 6DJ multiplets. The EPR spectra of Gd3+ ions in gadolinium–tellurite system exhibit two broad EPR signals at g ∼ 2.0 and g ∼ 6.

► The gradual addition of the gadolinium nitrate content generates changes of the basic structural units of the glass matrix.
► The UV–VIS absorption data seems to be influenced by the structural modifications of the host vitreous matrix.
► The EPR spectra of Gd3+ ions in gadolinium–tellurite system exhibit two broad EPR signals at g ∼ 2.0 and g ∼ 6.