Anand, V.K.; Adroja, D.T.; Britz, D.; Strydom, A.M.; Taylor, J.W.; Kockelmann, W.: Crystal-field states of Kondo lattice heavy fermions CeRuSn3 and CeRhSn3. Physical Review B 94 (2016), p. 014440/1-11
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Inelastic neutron scattering experiments have been carried out to determine the crystal-field states of the Kondo lattice heavy fermions CeRuSn3 and CeRhSn3. Both the compounds crystallize in LaRuSn3-type cubic structure (space group Pm¯3n) in which the Ce atoms occupy two distinct crystallographic sites with cubic (m¯3) and tetragonal (¯4m.2) point symmetries. The INS data of CeRuSn3 reveal the presence of a broad excitation centered around 6–8 meV, which is accounted by a model based on crystal electric field (CEF) excitations. On the other hand, the INS data of isostructural CeRhSn3 reveal three CEF excitations around 7.0, 12.2, and 37.2 meV. The neutron intensity sum rule indicates that the Ce ions at both cubic and tetragonal Ce sites are in Ce3+ state in both CeRuSn3 and CeRhSn3. The CEF level schemes for both the compounds are deduced. We estimate the Kondo temperature TK = 3.1(2) K for CeRuSn3 from neutron quasielastic linewidth in excellent agreement with that determined from the scaling of magnetoresistance which gives TK = 3.2(1) K. For CeRhSn3, the neutron quasielastic linewidth gives TK ≈ 4.6 K. For both CeRuSn3 and CeRhSn3, the ground state of Ce3+ turns out to be a quartet for the cubic site and a doublet for the tetragonal site.