Defect-property correlations in garnet crystals. V. Energy transfer in luminescent yttrium aluminum-yttrium iron garnet solid solutions

The absorption and luminescence spectra of yttrium aluminum garnet single crystals doped with iron have been studied. At low levels of iron doping, the intensity of the defect photoluminesence at 320 nm decreases with increasing iron concentration, as a result of energy transfer to Fe⁺³ ions which luminesce at 800 nm. Further increases in iron concentrations eliminate luminescence at all wavelengths. Differences between the absorption bands of iron in octahedral and tetrahedral sites, and inter-ion charge transfer processes are discussed.