Effect of cation size at Gd and Al site on ce energy levels in Gd[sub 3](GaAl)[sub 5]O[sub 12] sintered pellets

Radioluminescence and reflectivity measurements performed on sintered powder pellets of garnet compositions R3GaxAl5-xO12 (where R: Lu, Gd, Sc, Y) have shown that replacing "R" in these compositions with ions of larger radius shifts the excited 5d states of Ce to lower energy, while increased ionic radius at Ga/Al sites shifts these levels to higher energy. Stokes shifts were also calculated and results were verified by comparing the performance of the pellets with that of single crystals.