Elaboration, Structures, and Phase Transitions for YFe2DxCompounds (x=1.3, 1.75, 1.9, 2.6) Studied by Neutron Diffraction

Optical spectroscopic studies of the compound CsGd2F7:Nd3+have been carried out with the purpose of determining the lanthanide ion site luminescence properties. These studies have been made at low temperatures with crystals containing 0.3 to 3 at.% of Nd3+ion substituting for Gd3+ions. The experimental results discussed here are based on the analysis of the absorption, fluorescence, and excitation spectra. We have shown the presence of seven absorber centers disposed in four groups. Three of them exhibit a substructure composed of two sites each. These Nd3+ion centers have been correlated with known crystallographic sites.