Eu3+ ion distribution in oxyfluoride glass nanocomposites

Assessment of activator distribution in lanthanide doped nanocomposites is an important and challenging task. Oxyfluoride glass ceramics have been chosen as a model system to characterize incorporation efficiency of Eu3+ ions in CaF2 nanocrystals using a combination of X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) techniques. Lattice constant changes induced by size mismatch of Eu3+ and Ca2+ ions have been used to evaluate Eu3+ content in CaF2. The distortion of CaF2 lattice due to incorporation of europium ions can be detected from EPR investigations via Gd3+ paramagnetic probe spectra. It is shown that ratio of different symmetry CaF2:Gd3+ centres and linewidth of EPR transitions can be used to monitor europium content in the crystalline phase of glass ceramics.