From Kondo semimetal to spin-glass behaviour in doped CeNi _1−δ Sn _{1+δ− x} Sb _x system

We investigate the properties of the off-stoichiometric CeNi1−δSn1+δ−x Sb x systems with δ ≈ 0.06 and 0 < x ≤ 0.22. Such a semimetallic CeNi1−δSn1+δ−x Sb x system is shown to transform into a Kondo semiconductor upon the substitution of about 2% of Sb for Sn. The effects of Sb doping on the low-temperature properties of CeNiSn were studied by means of electrical resistivity, magnetic susceptibility and specific heat. We interpret the ground state properties of the series of CeNi1−δSn1+δ−x Sb x compounds as resulting from the change in carrier number acting together with the hybridisation between the 4f electrons and the conduction electrons. For the Kondo semiconductor state we observe the scaling law χρ = const. of the susceptibility χ and the resistivity ρ, which is regarded as the basic feature for this class of materials, as was reported earlier. The magnetic properties of the system gradually evolve from the Kondo semimetallic state to the spin-glass behaviour when the Sb doping increases.