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).

Electronic Raman Spectroscopy and Magnetic Susceptibilities

“…Each crystal field component in the split L S J manifolds of these ions belongs to one of the four representations of the group D,. Electronic Raman transitions between such levels have been observed (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) in rare earth garnet crystals, and the intensity of each transition is related to the value of an element of a scattering matrix. From the form of this matrix the scattering tensor for transitions of the individual rare earth ions at their crystallographic sites can be determined.…”