  The heavy-fermion system CeCu_{6-x}Au_x exhibits a quantum critical point at
x_c = 0.1 separating nonmagnetic and magnetically ordered ground states. The
pronounced non-Fermi-liquid behavior at x_c calls for a search for the relevant
quantum critical fluctuations. Systematic measurements of the inelastic neutron
scattering cross section S(q,omega) for x = 0.1 reveal rod-like features in the
reciprocal ac plane translating to two-dimensional (2d) fluctuations in real
space. We find 3d magnetic ordering peaks for x = 0.2 and 0.3 located on these
rods which hence can be viewed as 2d precursors of the 3d order.

Strongly Correlated Electrons