Photon energy dependence of the perpendicular geometry magnetic circular dichroism in the 2p3p3p resonant photoemission from Ni

The magnetic circular dichroism in the perpendicular geometry of the resona nt 2p3p3p photoemission (PE) spectroscopy has been investigated in metallic Ni as a function of the photon energy across the Ni Lj absorption edge. Wi thin the experimental error bars, the photon energy dependence of the PE di chroism signal is the same as the one shown by the magnetic circular dichro ism of the corresponding x-ray absorption (XMCD), obtained in the collinear geometry. This is attributed to the fact that, in metal Ni, the orbital [L -z] and dipolar [T-z] moments are smaller than the spin angular moment [S-z ]. The latter is the dominating term in both the expressions that give the integrated values of the PE dichroism or XMCD intensities, Although the res pective photon energy dependence is very similar, the normalized PE dichroi sm intensity is a factor similar to 5.6 smaller than the normalized XMCD si gnal, while only a factor similar to 1.6 is expected from theoretical consi derations. This factor is observed even below the L-3 threshold, thus we ex clude that the small intensity of the perpendicular geometry dichroism in t he Ni 2p3p3p resonant photoemission is due to fast relaxation processes in the intermediate state.