  One-band Hubbard model with transverse anisotropy is considered at density of
electrons $n=0.4$. It is shown that when the anisotropy is appropriately
chosen, the ground state is ferromagnetic with magnetic order perpendicular to
the anisotropy. The increasing of the ratio $\frac tU$, where $t$ is the
hopping parameter and $U$ is the Coulomb repulsion, decreases the Curie
temperature, and the system arrives at the quantum critical point $(T_C=0)$.
The result is obtained introducing Schwinger bosons and slave Fermions
representation of the electron operators. Integrating out the spin-singlet
Fermi fields an effective Heisenberg model with ferromagnetic exchange constant
is obtained for vectors which identifies the local orientation of the spin of
the itinerant electrons. The amplitude of the spin vectors is an effective spin
of the itinerant electrons accounting for the fact that some sites, in the
ground state, are doubly occupied or empty. Owing to the anisotropy, the magnon
fluctuations drive the system to quantum criticality and when the effective
spin is critically small these fluctuations suppress the magnetic order.
