Dense Kondo Effect in Caged Compound CeRu₂Zn₂₀

Abstract

We prepared single crystals of the caged compound CeRu2Zn20 by the flux method, and measured the magnetization, magnetic susceptibility, specific heat, and electrical resistivity. The lattice constant measured at room temperature suggests that the Ce ion is trivalent in this compound. The temperature dependence of magnetic susceptibility obeys the Curie–Weiss law with the effective Bohr magneton of Ce3+ at high temperatures. However, at low temperatures, CeRu2Zn20 indicates no phase transition down to 2 K and shows typical behaviors of a heavy Fermion system; the enhanced magnetic susceptibility χ0, the enhanced electronic specific-heat coefficient γ0, and the electrical resistivity with the temperature dependence of \(AT^{2}\), although these parameters somewhat depend on samples. The Wilson ratio \(R_{\text{W}}\) of χ0/γ0 is approximately 2, which does not depend on samples. A/γ0 is plotted on the line of \(N = 2\) in the new Kadowaki–Woods plots. The Kondo temperature \(T_{\text{K}}\) is roughly estimated from the present experiments; it ranges from 25 to 38 K depending on samples. These characteristics are typical of dense Kondo compounds.