Single-Site Non-Fermi Liquid Behaviors in a Diluted 4$f^2$ System Y${}_{1-x}$Pr${}_x$Ir${}_2$Zn${}_{20}$

Electrical resistivity $\rho (T)$ and specific heat $C(T)$ measurements have been made on the diluted 4$f^2$ system Y(Pr)Ir${}_2$Zn${}_{20}$. Both data of $\rho$ and magnetic specific heat $C_{\mathrm{m}}$ per Pr ion are well scaled as a function of $T\mathrm{/}{T}_0$, where $T_0$ is a characteristic temperature of non-Fermi liquid (NFL) behaviors. Furthermore, the temperature dependences of $\rho$ and $C_{\mathrm{m}}\mathrm{/}T$ agree with the NFL behaviors predicted by the two-channel Kondo model for the strong coupling limit. Therefore, we infer that the observed NFL behaviors result from the single-site quadrupole Kondo effect due to the hybridization of the 4$f^2$ states with multi-channel conduction electrons.