NEUTRON-SCATTERING EXPERIMENTS ON YBXCU4 AND ERXCU4 (X=AU,PD,AND AG)

Temperature-dependent neutron scattering experiments with incident energies in the range 350 meV have been performed on polycrystalline samples of the heavy-electron system YbXCu4, as well as the stable 4f-moment compounds ErXCu4 and the nonmagnetic reference materials LuXCu4, with X=Au, Pd, and Ag. The quasielastic linewidth of the YbXCu4 compounds is determined as a function of temperature. For YbAuCu4 a quantitative crystal-field analysis is applied to the observed inelastic response, while the data for the strongly 4f-delocalized compound YbAgCu4 are discussed in terms of a possible crystal-field interpretation and various theoretical models for heavy-electron systems. © 1990 The American Physical Society.