Investigation of the quantum phase transition in CeCu6-xAux

Recent experiments on the quantum phase transition between nonmagnetic (x less than or equal to x(c)) and magnetically ordered (x > xv) CeCu6-x Au-x alloys, occurring at a critical concentration x(c) approximate to 0.1 are reviewed. In particular, we investigate how the q-dependence of the critical fluctuations observed for x = 0.1 by inelastic neutron scattering evolve when moving away from the critical concentration. We also explore the fluctuations when a magnetically ordered alloy (x = 0.2) is exposed to a magnetic field suppressing the magnetic order. Finally, we address the question whether at the quantum phase transition the Kondo temperature vanishes, i.e. the heavy quasiparticles loose their identity, as proposed by recent theories.