Wave-vectorand magnetic-fielddependent spin fluctuations in the heavy-fermion systemCeCu6

Abstract
We have performed neutron-scattering measurements on a single crystal of CeCu6 in applied magnetic fields from 0 to 6.4 T. The observed momentum-dependent magnetic scattering implies the existence of short-range antiferromagnetic correlations. While it induces no resonances, the field broadens the spectra considerably at T=0.4 K. An effective Hamiltonian which incorporates both single-impurity Kondo properties and antiferromagnetic Ruderman-Kittel-Kasuya-Yosida interactions describes our data.