  We study the effects of quenched charge disorder on the phase reconstruction
near itinerant ferromagnetic quantum critical points in three spatial
dimensions. Combining a replica disorder average with a fermionic version of
the quantum order-by-disorder mechanism, we show that weak disorder
destabilizes the ferromagnetic state and enhances the susceptibility towards
incommensurate, spiral magnetic ordering. The Goldstone modes of the spiral
phase are governed by a 3d-XY model. The induced disorder in the pitch of the
spiral generates a random anisotropy for the Goldstone modes, inducing vortex
lines in the phase of the helical order and rendering the magnetic correlations
short ranged with a strongly anisotropic correlation length.
