H. Michor, J.G. Sereni, M. Giovannini, E. Kampert, L. Salamakha, G. Hilscher, E. Bauer:

"Elucidating the lack of magnetic order in the heavy-fermion CeCu";_{2}Mg

Physical Review B,95(2017), 115146-1 - 115146-7.

Magnetic, transport, and thermal properties of CeCu2Mg are investigated to elucidate the lack of magnetic order in this heavy-fermion compound with a specific heat value, Cmag/T |T→0 ≈ 1.2 J/mol K2 and robust effective magnetic moments (μeff ≈ 2.46μB). The lack of magnetic order is attributed to magnetic frustration favored by the hexagonal configuration of the Ce sublattice. In fact, the effect of magnetic field on Cmag/T and residual resistivity ρ0 does not correspond to that of a Fermi liquid (FL) because a broad anomaly appears at Tmax ≈ 1.2 K in Cmag(T )/T , without changing its position up to μ0H = 7.5 T. However, the flattening of Cmag/T |T→0 and its magnetic susceptibility χT→0, together with the T 2 dependence of ρ(T), reveal a FL behavior for T < 2 K which is also supported by Wilson and Kadowaki-Woods ratios. The unusual coexistence of FL

and frustration phenomena can be understood by placing paramagnetic CeCu2Mg in an intermediate section of a frustration-Kondo model. The entropy, Smag, reaches 0.87 R ln 6 at T = 100 K, with a tendency to approach the expected value Smag = R ln 6 of the J = 5/2 ground state of Ce3+.

heavy-fermion, magnetic frustration, high magnetic field studies, low temperatures

http://dx.doi.org/10.1103/PhysRevB.95.115146

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