The quadrupolar contribution to x-ray magnetic circular dichroism in REZn compounds

X-ray magnetic circular dichroism experiments on REZn single crystals (RE = Gd, Tb, Dy, Ho and Er) performed at the rare-earth L-2,L-3 edges show important quadrupolar contributions whose final states are the empty 4f orbitals. Calculations of the dichroic spectra have been performed using first-principle calculations with a treatment of the 4f states based on the LSDA + U (LSDA: local spin density approximation) method and including the spin-orbit coupling. The good agreement between experimental and calculated spectra allows a detailed analysis of the quadrupolar and dipolar contributions to the experimental spectra at the rare-earth L edges. Complementary study of the Zn K edge in HoZn reveals the magnetism induced on the Zn atoms.