  Coherent electronic transport through a molecular device is studied using
non-equilibrium Green's function (NEGF) formalism. Such device is made of a
carbon nanowire which is connected to ferromagnetic electrodes. The molecule
itself is described with the help of Hubbard model (Coulomb interactions are
treated by means of the Hartree-Fock approximation), while the coupling to the
electrodes is modeled through the use of a broad-band theory. It was shown that
magnetoresistance varies periodically with increasing the length of atomic wire
(in the linear response regime) and oscillates with increasing of bias voltage
(in the nonlinear response regime). Since the TMR effect for analyzed
structures is predicted to be large (tens of percentage), considered junctions
seem to be suitable for application as a magnetoresistive elements in the
future electronic circuits.
