Growth of LaBGeO₅ crystal fibers by the micro‐pulling down technique

Abstract

The LaBGeO 5 compound (LBGO) was prepared by solid state reaction at 1050°C and characterized by XRD and DTA analysis. The direct growth of LBGO fibers from the melt using micro-pulling down technique was unsuccessful because of its high viscosity. The study of the LBGO-LiF phase diagram showed that LiF could be considered as a convenient flux to reduce viscosity of the melt during the growth process. Several crystal fibers were then grown and characterized by Raman spectroscopy. To decrease the high volatility of LiF, B 2 O 3 was added to the melt. A white cloudy fiber was obtained from LiF-B 2 O 3 flux and checked by Raman spectroscopy and scanning electron microscopy.

Highlighting of LaF3 Reactivity with SiO2 and GeO2 at High Temperature

“…We have not found a Raman spectrum of La 2 Ge 2 O 7 in the literature to compare it with that of Ge-La after thermal treatment. However, Figure 13 gives us an idea of the expected shape; we compared our spectrum with that of LaBGeO 5 [36]. The comparison of these two Raman spectra tends to show that the obtained product could be some type of lanthanum germanium oxide, especially the peaks around 600, 780, 800 and 850 cm −1 .…”