title: Glassy spin dynamics in non-fermi-liquid UCu5-xPdx, x = 1.0 and 1.5.
abstract: Local f-electron spin dynamics in the non-Fermi-liquid heavy-fermion alloys UCu5-xPdx, x = 1.0 and 1.5, have been studied using muon spin-lattice relaxation. The sample-averaged asymmetry function G(t) indicates strongly inhomogeneous spin fluctuations and exhibits the scaling G(t,H) = G(t/H(gamma)) expected from glassy dynamics. At 0.05 K gamma(x = 1.0) = 0.35+/-0.1, but gamma(x = 1.5) = 0.7+/-0.1. This is in contrast to inelastic neutron scattering results, which yield gamma = 0.33 for both concentrations. There is no sign of static magnetism approximately greater than 10(-3)(B)/U ion in either material above 0.05 K. Our results strongly suggest that both alloys are quantum spin glasses.
authors.affiliation: Department of Physics, University of California, Riverside, California 92521-0413, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: MacLaughlin
authors.forename: O O
authors.initials: OO
authors.lastname: Bernal
authors.forename: R H
authors.initials: RH
authors.lastname: Heffner
authors.forename: G J
authors.initials: GJ
authors.lastname: Nieuwenhuys
authors.forename: M S
authors.initials: MS
authors.lastname: Rose
authors.forename: J E
authors.initials: JE
authors.lastname: Sonier
authors.forename: B
authors.initials: B
authors.lastname: Andraka
authors.forename: R
authors.initials: R
authors.lastname: Chau
authors.forename: M B
authors.initials: MB
authors.lastname: Maple