Magneto-optical investigations of rare earth doped sol-gel derived silicate xerogels

Rare-earth doped xerogels (Eu³⁺, Sm³⁺, Ho³⁺, Pr³⁺) were prepared by using the sol-gel method and their magneto-optical and optical properties have been studied. The Magnetic Circular Dichroism (MCD) spectra are quite similar to those recorded in the RE-doped fluorozirconate glasses; the fine structures shown by the MCD spectra are better resolved compared to the optical absorption spectra. The MCD technique has been correlated with optical measurements in order to investigate the site symmetry in the particular case of Eu³⁺-doped xerogel and oxyfluoride glasses. In the xerogel, coordination symmetry around the Eu³⁺ ions is close to D_3h and is lower in the oxyfluoride glass.