Non-Fermi-liquid behavior and magnetic fluctuations at the quantum phase transition in CeCu6-xAux

CeCu6-xAux has become a prototype heavy-fermion system where, starting from not magnetically ordered CeCu6, Au doping introduces long-range incommensurate antiferromagnetism for x > x(c) approximate to 0.1. At the critical concentration x(c), the unusual magnetic fluctuations probed by inelastic neutron scattering lead to non-Fermi-liquid behavior, i.e. to anomalous low-temperature thermodynamic and transport properties. In magnetically ordered alloys, hydrostatic pressure can be employed to tune the magnetic-nonmagnetic transition. The effect of pressure in suppressing the antiferromagnetic order is contrasted by the effect of a magnetic field by way of a detailed study for x = 0.2.