Yb3+- and CaF2 nanocrystallites-containing oxyfluorogermanotellurite glass-ceramics

Abstract A new 30 GeO 2 -30 TeO 2 -15 ZnO-10 Na 2 CO 3 -10 CaF 2 -3 La 2 O 3 -2 YbF 3 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 Yb 3+ ions dissolved in the glass and, presumably, in the nanocrystallites, were investigated by absorption and emission spectroscopies (including anti-Stokes emissions from Tm 3+ and Er 3+ impurities), fluorescence transients and magnetic susceptibility measurements. It was found that the Yb 3+ ions experimental lifetime and average effective magnetic moment, as well as Tm 3+ and Er 3+ ions anti-Stokes emission intensities, increase with increasing crystallization state of the initial glass.