Interplay between spin-glass and non-Fermi-liquid behavior inY1−xUxPd3

Abstract

We report the results of a study of the ac and dc magnetic susceptibilities of ${\mathrm{Y}}_{1\ensuremath{-}x}{\mathrm{U}}_{x}{\mathrm{Pd}}_{3}$. The magnetic properties of the system gradually evolve from the spin-glass (SG) behavior observed for $x=0.4$ to the non-Fermi-liquid (NFL) ground state that develops at $x=0.2$. For $x=0.4$, the SG properties are remarkably similar to those found in canonical spin glasses. We have been able to analyze our data in terms of critical slowing down when $T$ approaches the critical temperature associated with a spin-glass freezing phase transition. The values obtained for the dynamic and static critical exponents [$z\ensuremath{\nu}=10\ifmmode\pm\else\textpm\fi{}1$, $\ensuremath{\beta}=0.9(1)$, $\ensuremath{\gamma}=1.8(2)$] support the existence of a true spin-glass phase transition in ${\mathrm{Y}}_{0.6}{\mathrm{U}}_{0.4}{\mathrm{Pd}}_{3}$. On the other hand, the evolution of magnetic properties with a decreasing U concentration suggests an interplay between the SG and NFL ground states. The ground state that finally appears for $x=0.2$ displays a temperature dependence of its low-field ac susceptibility consistent with the prediction of the Griffith's phase model of NFL behavior. The role played by compositional disorder in the development of the NFL state is discussed.