Investigation of non-Fermi-liquid behavior in CeCu6-xAux

Non-Fermi-liquid (NFL) behavior has been observed in CeCu6-xAux at the onset of antiferromagnetic order, either for x=xc=0.1 at pressure p=0, or for x=0.3 by pressure-tuning the Neel temperature TN to zero. We report on a detailed study in the vicinity of xc exploring the NFL behavior, i.e. the specific heat C divided by temperature T varying as C/T∝-ln(T/T0) and the magnetization M measured in B=0.1 T exhibiting a cusp for T→0. A magnetic field which likewise suppresses magnetic order does not induce NFL behavior when TN→0 as shown for a sample with x=0.2. This supports the idea that NFL behavior arises from an abundance of low-lying spin excitations. The Kondo temperatures are determined from the high-field specific heat. (orig.)