Yb~(3+)- and CaF_2 nanocrystallites-containing oxyfluorogermanotellurite glass-ceramics

摘要

A new 30 GeO2-30 TeO2-15 ZnO-10 Na2CO3-10 CaF2-3 La2O3-2 YbF3 glass composition was synthesized and submitted to several heat treatments to provoke nanocrystallization in its bulk. The formation of nanocrystallites was evidenced by high resolution transmission electron microscopy and X-ray diffraction, and their nature and size was characterized. The spectroscopic and magnetic properties of the Yb3+ ions dissolved in the glass and, presumably, in the nanocrystallites, were investigated by absorption and emission spectroscopies (including anti-Stokes emissions from Tm3+ and Er3+ impurities), fluorescence transients and magnetic susceptibility measurements. It was found that the Yb3+ ions experimental lifetime and average effective magnetic moment, as well as Tm3+ and Er3+ ions anti-Stokes emission intensities, increase with increasing crystallization state of the initial glass.