Caracterização estrutural e óptica de vidros teluretos dopados com íons Nd3+

Abstract

The structural properties of tellurite glasses were studied in this work using the Nd2O3 doped composition 65TeO2-15Li2O-20ZnO in concentrations of 0.00; 0.25; 0.35;

0.50; 0.75 and 2.00 mol% as well as the Judd-Ofelt calculations. The samples were pre- pared by melting quenching technique and submitted to X-Ray Diffraction (XRD), Ar- quimedes’ Density, Raman spectroscopy, Fourier Transform Infrared (FTIR) and Dif- ferential Scanning Calorimetry (DSC) analysis. Lastly we obtained the optical analysis

by Ultraviolet–Visible Spectroscopy (UV-Vis-NIR) which was used for the Judd-Ofelt calculations. The DRX results present a typical amorphous nature common in vitreous materials. The density shows a expected behavior with a small increase in molar volume

and a higher increase in molar mass, resulting in a density increase with grater quanti- ties of neodymium, we also obtained a decrease in the Oxygen Package Density (OPD).

The Raman spectroscopy presented a increase of TeO3 and TeO3+1 units and a reduction of Te-O-Te connections.We also saw a slight reduction in both TeO4 units and Te-O-Te connections in the FTIR results, is also noted a increase in TeO3 and TeO3+1 structures,

confirming the Raman results. By the DSC technique is shown a vitreous stability re- duction in low concentrations, which increases when more dopant is added. We observe

in UV-Vis-NIR spectroscopy all the standard absorption spectrum, we also indentify the hypersensitive level of Nd3+, given by 4

I9/2 →4 G5/2 +2 G7/2 transition. Using said results we obtained the Ω2,4,6 parameters, Ω2 presenting a decrease with increased concentrations, tending to a higher matrix organization, Ω4 and Ω6 have decreasing behaviors and concur to what was expected. Is also noted that to lower concentrations Ω6 > Ω4, implying in a decay to 4

I11/2 state, meanwhile to higher concentrations the Ω4 > Ω6 pattern is taken,

implying in a decay to the ground state. Is alto taken in account the samples quench- ing in 0.50% concentration. The theoretical radioactive transition rate, ramification ratio

and lifetime were taken and present a increase probability to transition to 4

I11/2 in lower concentrations (≈ 47.67%) and higher probability do decay to the ground state in higher concentrations (≈ 47.60%), is also taken a higher lifetime (287.09 μs) when compared to similar doped materials. The absorption cross section presents a better potential in applied lasers when compared to other tellurite glasses with the same dopant, showing bigger values to lower concentration samples.