Single-ion scaling and unconventional Kondo behavior in the electrical resistivity of the U 1 − x Th x Pd 2 Al 3 system

We report measurements of the temperature T dependence of the electrical resistivity \ensuremath{\rho} of the ${\mathrm{U}}_{1\ensuremath{-}x}{\mathrm{Th}}_{x}{\mathrm{Pd}}_{2}{\mathrm{Al}}_{3}$ system for thorium concentrations $0.6l~xl~1.0$ in the temperature range $0.02\mathrm{K}l~Tl~300\mathrm{K}.$ These measurements reveal an unconventional Kondo effect with an effective Kondo temperature ${T}_{K}\ensuremath{\approx}20\mathrm{K},$ which is independent of thorium concentration. The $\ensuremath{\rho}(T)$ data below ${T}_{K}$ scale with U concentration $(1\ensuremath{-}x)$ and ${T}_{K}$ in agreement with the scaling of $C(T)$ and $\ensuremath{\chi}(T)$ at low temperature that was previously established. Analysis of the data below 20 K indicates that the electrical resistivity in the non-Fermi-liquid regime saturates as a power law at the lowest temperatures with the form $\ensuremath{\rho}(T)\ensuremath{\sim}1\ensuremath{-}{a(T/T}_{K}{)}^{n}$ with $n\ensuremath{\sim}1.5.$