Raman Determination of 2F7/2 Crystal Field Levels in YbAlG and YbGaG

Abstract

Raman scattering from YbAlG and YbGaG at 80 K was investigated in order to obtain reliable crystal field levels of the Yb3+(2F7/2) ground manifold. Our 2F7/2 assignments for YbGaG (0, 546, 610, and 624 cm−1) are complete (four levels predicted for D2 site symmetry) and are consistent with the levels determined from absorption by Buchanan et al. [Phys. Rev. 159, 245 (1967)]. For YbAlG our assignments (0, 587, 621 cm−1, and a doublet at 758 cm−1) differ significantly from the work of Buchanan et al. who may have adopted the wrong assignments due to numerous vibronic side bands present in their original absorption spectra. Further confirmation of our results for YbAlG was provided by a companion study of LuAlG because of its closed 4f shell (no electronic scattering) and the nearly identical masses of Lu and Yb (i.e., equivalent phonon spectrum).