Ce3+, Fe3+-Induced Optical Absorption in Ce, Fe:YAG Prepared by Coprecipitation

To investigate optical transitions induced by Ce3+ and Fe3+ in garnet, Ce, Fe-substituted Y3Al5O12 (Ce, Fe:YAG) ceramics have been successfully prepared by urea coprecipitation and subsequent heat treatment at temperatures as low as 820–880° C. Absorption spectra of Y2.9Ce0.1Al5-x Fex O12 (x=0–1.0), estimated by diffuse reflection measurements, showed that, as x increases, the absorption peak at h ν=2.7 eV due to the 4f–5d transition in Ce3+ remains unchanged, while a new broad absorption peak occurs at around 1.4 eV. These results indicate that the transition at 1.4 eV observed in Ce-substituted iron garnet, which strongly enhances the magneto-optical effect, is not the 4f–5d transition in Ce3+ shifted by the influence of the next nearest neighbor ions.