  A quantum dot coupled to ferromagnetically polarized one-dimensional leads is
studied numerically using the density matrix renormalization group method.
Several real space properties and the local density of states at the dot are
computed. It is shown that this local density of states is suppressed by the
parallel polarization of the leads. In this case we are able to estimate the
length of the Kondo cloud, and to relate its behavior to that suppression.
Another important result of our study is that the tunnel magnetoresistance as a
function of the quantum dot on-site energy is minimum and negative at the
symmetric point.
