Low-energy spin fluctuations of the heavy-Fermion compound CeNi_2Ge_2: origin of non-Fermi liquid behavior

Abstract

Neutron scattering shows that non-Fermi-liquid behavior of the heavy-Fermion compound CeNi_2Ge_2 is brought about by development of low-energy spin fluctuations with an energy scale of 0.6 meV. They appear around antiferromagnetic wave vectors $(1/21/20)$ and $(003/4)$ at low temperatures, and coexist with high-energy spin fluctuations with an energy scale of 4 meV and a modulation vector $(0.23,0.23,1/2)$. The energy dependence of the spin fluctuations is a peculiar character of CeNi_2Ge_2 which differs from typical heavy-Fermion compounds, and suggests importance of low-energy structures of quasiparticle bands.

4 pages, 2 figures, Proceedings of SCES 2002 (Krakow-Poland), Contact: [email protected]