Magnetic correlations in single-crystalline CeNi₂Ge₂

Abstract

The antiferromagnetic correlations in the non-Fermi-liquid compound CeNi2Ge2 have been measured on single crystals using inelastic neutron scattering. The spin fluctuations with a characteristic energy of 4 meV are centred at the incommensurate wave vector (0.23, 0.23, 0.5), which is similar to where magnetic order develops in the related compound CeCu2Ge2. The magnetic correlations are anisotropic, with a quasi-two-dimensional extension along the [110] direction, implying that the moments are mostly correlated in the [110] planes. With increasing temperature, the correlated signal decreases, and above T* ≈ 30 K the magnetic scattering appears to be wave-vector independent.