Electronic Raman Spectra: Crystal Field in Terbium Aluminum Garnet and Europium Gallium Garnet

Abstract

The crystal-field splittings of the $^{7}F$ multiplet of ${\mathrm{Eu}}^{3+}$ and ${\mathrm{Tb}}^{3+}$ have been determined in europium gallium garnet (EuGaG) and terbium aluminum garnet (TbAlG) from light scattering, fluorescence, and absorption spectra. The data were used to derive a set of crystal-field parameters for the two garnet systems. In these calculations the Hamiltonian appropriate for the ${D}_{2}$ symmetry of the rare-earth sites and also the mixing of different $J$ states by the crystal field were taken into account. From the eigenfunctions derived in this way the magnetic-susceptibility-versus-temperature curve was calculated for TbAlG.