Local magnetic moments in doped BaFe2As2

We present a comparative calculation of the high critical temperature superconductor doped BaFe2As2 with its parent compound at the electron correlation level by the embedded cluster method; the electron correlation is calculated at the second order M{\o}ller-Plesset perturbation theory level. For the pure material we consider the Ba Fe5As8 cluster, for the doped material the central Fe is substituted by Co or Ni. The analysis of orbital populations in the doped material reveals a charge density increase on the central impurity with respect to the charge density of the central Fe atom of the undoped case. On the other hand, the spin-density analysis allows to determine the distribution of the spin density on the neighboring of the central impurity. Both analysis show how the interaction between the central impurity and its neighboring Fe atoms participates to the formation mechanism of the local magnetic moments.