  We consider local magnetic moments coupled to conduction electrons with
on-site attraction, in order to discuss the interplay between pairing and
magnetic order. We probe the ground state properties of this model on a
one-dimensional lattice through pair binding energies and several correlation
functions, calculated by means of density-matrix renormalization group. A phase
diagram is obtained (for fixed electron density 1/3), from which we infer that
coexistence between magnetic order and superconductivity is robust, at the
expense of a continuous distortion of the magnetic arrangement of the local
moments, as evidenced by a strong dependence of the characteristic wave vector
k* with the coupling constants. This allows us to understand some trends of the
coexistence, such as the influence of the rare earth on k*, as observed
experimentally in the borocarbides.
