Mössbauer-Effect Study of Europium in Glass

Mössbauer spectra have been obtained for ${}_{}{}^{151}{}_{}{}^{}\mathrm{Eu}$ in some silicate and phosphate glasses. In the silicate glasses ${\mathrm{Eu}}^{3+}$ behaves very much as it does in ${\mathrm{Eu}}_2$ ${\mathrm{O}}_3$. The isomer shift relative to ${\mathrm{Eu}}_2$ ${\mathrm{O}}_3$ is ∼0.1 mm/sec. Some broadening of the line can be attributed to unresolved quadrupole splitting and to disorder in the glass structure. The recoilless fraction is 0.33. Measurements made at elevated temperatures indicate a complicated dependence of isomer shift on temperature cycling. In europium phosphate glass the isomer shift is ∼-0.3 mm/sec, and the linewidth is approximately the same as for the silicate glasses.