Gamma-induced absorption spectra as a new method for RE-ion environment study in fluorophosphate glasses

摘要

Doped fluorophosphate glasses based on pseudo-binary system: barium metaphosphate Ba(PO_3)_2- usovite MgCaSrBaAl_2F_(14), are studied by means of fluorescence, induced ESR and optical absorption spectra. Doping the glass, containing 5 and 7 mol% Ba(PO_3)_2 with TbF_3 and EuF_3 results in drastic changes of color and paramagnetic center numbers correspondingly. Post-irradiation process results in separation of the spectra analyzed into groups in dependence of Tb~(3+) ion concentration. The crucial concentration, dividing two concentration ranges is not more than 0.02 mol%. It is supposed that the local environment of Tb~(3+) ion doped up to concentration mentioned is preferably phosphate. Estimates of Eu~(3+) ion concentration that have preferably phosphate groupings in their environment result from concentration dependence of PO_4~(2-) centers and produce the value of approximately 0.01 mol%. Close values of two crucial concentrations is interpreted in terms of doped ion segregation model.