Susceptibility inhomogeneity and non-Fermi-liquid behavior in nominally ordered UCu4Pd

Muon spin rotation experiments on a stoichiometric sample of the non-Fermi-liquid (NFL) heavy-fermion compound UCu4Pd, in which recent neutron scattering experiments suggest an ordered structure, indicate that the U-ion susceptibility is strongly inhomogeneous at low temperatures. We argue that this is due to residual disorder, which also dominates NFL behavior. The data yield a short correlation length (≲1 lattice spacing) and a rapid low-temperature U-moment relaxation rate (≳1012 s-1), which constrain cluster-based models of NFL behavior.