NMR studies of the heavy fermion alloy Ce(Cu1-xNix)2Ge2

Abstract

A detailed 63Cu NMR investigation is presented for the heavy-fermion system Ce(Cu1-xNix)2Ge2, focusing especially on the alloying induced transition from magnetic order to pure Kondo-like behavior. The broadening of the resonance line and the temperature dependence of the spin-lattice relaxation rate 1/T1 are studied in full detail. We provide experimental evidence for the appearance of heavy-fermion band magnetism for concentrations x=0.6 and x=0.7. For x=0.8 the spin-lattice relaxation rate 1/T1 follows a logarithmic temperature dependence which we interpret as a fingerprint of a non-Fermi-liquid behavior. Finally, 1/T1 is compared to the dynamic structure factor S(Q,ω) as determined in inelastic-neutron-scattering experiments.