Anomalous magnetic properties and non-Fermi-liquid behaviour in single crystals of the Kondo lattice CeNiGe2−xSix

• Published in: Journal of physics. Condensed matter Vol. 16; no. 46; pp. 8323 - 8334
• Main Authors: Kim, D Y, Ryu, D H, Hong, J B, Park, J-G, Kwon, Y S, Jung, M A, Jung, M H, Takeda, N, Ishikawa, M, Kimura, S
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 24.11.2004; Institute of Physics
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic conduction in metals and alloys; Electronic transport in condensed matter; Exact sciences and technology; Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Physics; Scattering mechanisms and kondo effect; Valence fluctuation, kondo lattice, and heavy-fermion phenomena; Antiferromagnetism; Magnetic specific heat; Local magnetic moment; Inorganic compounds; Electrical conductivity; Cerium silicides; Quantum phase transition; Cerium Germanides; Transition element compounds; Nickel silicides; Heavy fermions; Anomalous properties; Two dimensional model; Rare earth compounds; Specific heat; Non Fermi liquid; Monocrystals; Kondo effect; Quaternary compounds; Exchange interactions; Nickel germanides; Magnetic properties
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/16/46/018

We report on the magnetic susceptibility, specific heat and electrical resistivity of the heavy fermion compounds CeNiGe2-xSix (&0leq x leq 1;). Compounds with x < 1 show antiferromagnetic order, which with increasing x shifts toward lower temperature owing to increased exchange coupling between the localized 4f magnetic moments and conduction electrons. Eventually, the magnetic order almost becomes absent, for x = 1. An anomaly observed in the specific heat is well interpreted by the Kondo model for a degenerate impurity spin J = 1/2 in the Coqblin-Schrieffer limit. A coherence peak indicative of the formation of a Kondo lattice is found in the electrical resistivity, whose features are consistent with the results for the specific heat. Interestingly, there is a significant deviation from Fermi-liquid behaviour at the critical concentration x = 1. This deviation is attributed to a quantum phase transition in a model with two-dimensional antiferromagnetic fluctuations.