SITE-SELECTIVE SPECTROSCOPY IN EU-3+ - LANTHANUM MAGNESIUM ALUMINATE

Pulsed resonance emission spectra for La1-xEuxMgAl11O19 are reported under excitation into the non-degenerate 5D0 <-- 7F0 transition of Eu3+ at 77 K. Emission spectra recorded under continuous-wave excitation into the same transition at liquid helium temperature were also examined. These results show clear evidence for the existence of only two distinct substitutional site distributions for Eu3+, with their 5D0 <-- 7F0 transitions between 577 and 579 nm. The suggestion of a third site distribution ca. 576 nm is also reported. Discrepancies concerning the number of Eu3+ substitutional sites and the positions of their corresponding 5D0 --> 7F0 peaks reported in other studies are addressed in the light of our results.