Crystal-field effects in the mixed-valence compounds Yb2M3Ga9 (M= Rh,   Ir)
  Magnetic susceptibility, heat capacity, and electrical resistivity measurements have been carried out on single crystals of the intermediate valence compounds Yb2Rh3Ga9 and Yb2Ir3Ga9. These measurements reveal a large anisotropy due apparently to an interplay between crystalline electric field (CEF) and Kondo effects. The temperature dependence of magnetic susceptibility can be modelled using the Anderson impurity model including CEF within an approach based on the Non-Crossing Approximation. 
N. O. Moreno, A. Lobos, A. A. Aligia, E. D. Bauer, S. Bobev, V.   Fritsch, J. L. Sarrao, P. G. Pagliuso, J. D. Thompson, C. ...