Magnetic behavior in UFe₂Zn₂₀ and URu ₂Zn₂₀ single crystals

The magnetic, electrical transport and thermodynamic properties of the compounds UFe₂Zn₂₀ and URu₂Zn₂₀ were studied on single-crystalline specimens over wide ranges of temperature and magnetic field. The results indicate that the two ternaries are paramagnetic moderately enhanced heavy fermion systems. Their physical behavior is governed predominantly by the hybridization of uranium 5f orbitals with electronic states of ligands, which brings about considerable delocalization of the 5f states.