Crystal field and magnetic ordering in the cubic Kondo lattice YbPdSb

Specific heat and 170Yb Mossbauer spectroscopy measurements performed in cubic YbPdSb show that the Yb3+ CEF ground state is the Γ8 quartet with a Kondo temperature T K ⋍ 8 K . A first-order magnetic transition is observed at T = 1 K; at T = 0.05 K, the Yb3+ spontaneous magnetic moment is 1.3 μB, markedly smaller than the saturated Γ8 magnetic moment (∼ 2 μB). The 170Yb Mossbauer spectra with applied magnetic field in the magnetically ordered phase show that the RKKY exchange is anisotropic and provide an estimation for TRKKY, which is found to be of the same order of magnitude as TK.