Inducement of non-Fermi-liquid behavior with a magnetic field

Using AE doping of the nearly magnetic heavy-fermion system CeCu6 to vary the onset of antiferromagnetism between T-N=0 and 0.8 K, we have found a large region of the phase diagram where magnetic field tan reach the quantum critical point (T-N-->0) with sufficiently strong antiferromagnetic correlations remaining to produce non-Fermi-liquid (NFL) behavior. In this field and composition regime, the CeCu6-xAgx samples exhibit the typical NFL temperature dependencies for the various measured parameters over a broad range of temperature down to 100 mK. Application of higher fields to these samples causes entry into the Fermi-liquid regime. Due to the ease of changing magnetic fields when establishing the phase diagram at low-temperatures, the increased efficacy of field suppression of T-N versus that achieved by pressure, and the fact that magnetic field does not change the volume as do both pressure and doping, magnetic field offers distinct advantages as a method for exploring the crossover between antiferromagnetic, non-Fermi-liquid, and Fermi-liquid behavior in the vicinity of the quantum critical point. [S0163-1829(98)51008-9].