A spectroscopic study of the monoclinic to tetragonal phase transition of the phosphor Eu3+:LiYO2 at 350 K

Fluorescence spectra of LiY 0.95 Eu 0.5 O 2 at 77, 300 and 370 K show evidence for a reversible monoclinic to tetragonal phase transition which occurs at 350±5 K. The crystal field parameters of Eu 3+ are determined in the C 1 and the D 2d sites of europium in the two phases