Phase transitions and non-Fermi-liquid behavior inUCu5−xPdxat low temperatures

Abstract

We report on measurements of the specific heat C and susceptibility $\ensuremath{\chi}$ on ${\mathrm{UCu}}_{5\ensuremath{-}x}{\mathrm{Pd}}_{x} (x=0,1,1.25,1.5,2).$ For $1<~x<~1.5,$ the results suggest that non-Fermi-liquid behavior, i.e., a divergence of $C/T$ and $\ensuremath{\chi}$ towards low temperatures, gives way to spin-glass freezing for $x=1$ and $x=1.5,$ whereas no indication of a magnetically ordered ground state is observed for $x=1.25$ down to $30 \mathrm{mK}.$ A description based on the model of the Griffiths phase yields exponents $\ensuremath{\lambda}$ determined from $C/T$ and $\ensuremath{\chi},$ which are compatible with each other.