Slow spin dynamics in non-fermi-liquid UCu5−xPdx, x=1.0 and 1.5

Abstract

Low-temperature muon spin-lattice relaxation measurements in the non-Fermi-liquid heavy-fermion alloys UCu5−xPdx, x=1.0 and 1.5, indicate inhomogeneously distributed f-electron spin fluctuation rates, and exhibit a time-field scaling of the muon relaxation function indicative of long-lived spin correlations. In UCu4Pd the scaling exponent γ is small and temperature independent. In UCu3.5Pd1.5γ varies with temperature, increasing with decreasing temperature similar to spin-glass AgMn. This suggests that the spin-glass state found for x≳2 in UCu5−xPdx modifies the low-frequency spin dynamics in UCu3.5Pd1.5.