Crystal-field effects in the mixed-valence compoundsYb2M3Ga9(M=Rh,Ir)

Abstract

Magnetic susceptibility, heat capacity, and electrical resistivity measurements have been carried out on single crystals of the intermediate valence compounds ${\mathrm{Yb}}_{2}{\mathrm{Rh}}_{3}{\mathrm{Ga}}_{9}$ and ${\mathrm{Yb}}_{2}{\mathrm{Ir}}_{3}{\mathrm{Ga}}_{9}$. 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.