  Magnetic properties of the two-dimensional t-t'-U model are investigated by
studying the static spin magnetic susceptibility as a function of momentum for
various temperatures. The calculations are performed by means of the Composite
Operator Method in the static approximation. By increasing the value of the t'
parameter the magnetic scattering in the reciprocal space evolves to an
isotropic structure. It is shown that the results are in qualitative agreement
with the experimental situation observed in LSCO and YBCO compounds.
