Analysis of the distribution of Tm3 + ions in LaF3 containing transparent glass-ceramics through X-ray absorption spectroscopy

•Tm incorporation in LaF3 was confirmed using a first coordination shell model.•The preferential inclusion of Tm in LaF3 crystals was confirmed and quantified.•Tm3 + concentration in LaF3 nano-crystals increases during crystallisation process.

Incorporation of rare-earth (RE) ions in the fluoride crystals of oxyfluoride glass-ceramics greatly improves the optical properties of these materials, such as the up-conversion emission. In this work, we present a study of this incorporation using X-ray absorption near-edge structure (XANES) spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. Both techniques allow quantifying the distribution of these ions in the glass matrix and the fluoride crystals. We found that 27% of Tm3 + ions are incorporated in LaF3 nano-crystals.