From Kondo semimetal to spin-glass behaviour in doped CeNi_1−δSn_1+δ−xSb_x system

Abstract

We investigate the properties of the off-stoichiometric CeNi_1−δSn_1+δ−x Sb _x systems with δ ≈ 0.06 and 0 < x ≤ 0.22. Such a semimetallic CeNi_1−δSn_1+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 CeNi_1−δSn_1+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.

Keywords:

• correlated systems
• Kondo effect
• quantum critical phenomena

Acknowledgements

The authors are grateful to Mrs. Alicja Hackemer for her assistance during the heat capacity measurements. This work was partly supported by the COST P-16 European Network Emergent Behaviour in Correlated Matters (ECOM) and the National Scientific Network Materials with Strongly Correlated Electrons (MSSE). One of us (JS) acknowledges Grant No 1 P03B 001 29 from the Ministry of Science and Higher Education.

Notes

Notes

1. A plateau in the monocrystalline CeNiSn samples in the temperature dependence of ρ(T) has been observed 33.

2. The heat capacity and thermal expansion results showed a kink at about 6 K and a feature at about 2 K. These anomalies were described as extrinsic and as originating from the presence of CeNi₂Sn₂ and Ce₃Ni₄Sn₃ impurities 15,37.