Non-Fermi Liquid Behavior and Griffiths Phase in f-Electron Compounds

We study the interplay among disorder, RKKY, and Kondo interactions in f -electron alloys. We argue that the non-Fermi liquid behavior observed in these systems is due to the existence of a Griffiths phase close to a quantum critical point. The existence of this phase provides a unified picture of a large class of materials. We also propose new experiments that can test these ideas. {copyright} {ital 1998} {ital The American Physical Society}