The effect of doping in CeNiSn has been studied by measurements of electrical resistivity, magnetic susceptibility, and specific heat for polycrystalline samples of ${\text{CeNi}}_{1-x}{\text{Rh}}_x\text{Sn}$. It was observed that the semimetallic compound CeNiSn transforms into a Kondo semiconductor upon the substitution of 2% of Rh for Ni. We show that the narrow Kondo-insulator gap formation can be associated with disorder-induced $f$-electron localization. The magnetic properties of the system gradually evolve from magnetic glassy state, observed for $0<x<0.08$, to non-Fermi-liquid (NFL) behavior, when the Rh doping increases. The series of ${\text{CeNi}}_{1-x}{\text{Rh}}_x\text{Sn}$ exhibits NFL behavior in the vicinity of a zero-temperature magnetic phase transition, which is associated with spin-glass-like ordering due to chemical substitution. The detailed investigations of magnetic properties with decreasing Rh concentration suggest an interplay between the spin-glass-like (glassy state) and NFL ground states for the concentration region $x<0.08$. On the basis of the experimental results, we propose a schematic phase diagram on the $T-x$ plane and demonstrate the rationale for the existence of a quantum critical point at $x_c\approx 0.08$.

• Received 26 February 2008

DOI:https://doi.org/10.1103/PhysRevB.77.245133