  Angle resolved-Auger-photoelectron coincidence spectroscopy (AR-APECS) has
been exploited to investigate the role that electron correlation plays in the
exchange-coupling at the ferromagnetic/antiferromagnetic interface of a Fe/CoO
bilayer growth on Ag(001). The effective correlation energy U$_{\textrm{eff}}$,
usually employed to assess the energy distribution of core-valence-valence
Auger spectra, has been experimentally determined for each possible combination
of the orbital (e$_g$ or t$_{2g}$) and the spin (majority or minority) of the
two valence electrons involved in the Auger decay. Coulomb and exchange
interactions have been identified and compared with the result obtained on the
Fe/Ag system. The presented analysis reveals in the Fe/CoO interface an
enhancement of the Coulomb interaction for the e$_g$ orbital and of the
exchange interaction for the t$_{2g}$ orbital with respect to the Fe/Ag case
that can be associated to the stronger electron confinement and to the exchange
coupling between the two layers, respectively.
