Spin fluctuations and non-Fermi-liquid behavior ofCeNi2Ge2

Neutron scattering shows that non-Fermi-liquid behavior of the heavy-fermion compound CeNi 2 Ge 2 is brought about by the development of low-energy spin fluctuations with an energy scale of 0.6 meV. They appear around the antiferromagnetic wave vectors (½ ½ 0) and (0 0 3/4) at low temperatures, and coexist with high-energy spin fluctuations with an energy scale of 4 meV and a modulation vector (0.23,0.23, ½). This unusual energy dependent structure of ImΧ(Q,E) in Q space suggests that quasiparticle bands are important.