M ay 1 99 8 Rare earth contributions to the X - ray magnetic circular dichroism at the Co K edge in rare earth - cobalt compounds investigated by multiple - scattering calculations

The X-ray magnetic circular dichroism (XMCD) has been measured at the Co K edge in hcp-Co and R-Co compounds (R=La, Tb, Dy). The structure of the experimental XMCD spectra in the near-edge region has been observed to be highly sensitive to the magnetic environment of the absorbing site. Calculations of the XMCD have been carried out at the Co K edge in Co metal, LaCo 5 and TbCo 5 within the multiple-scattering framework including the spin-orbit coupling. In the three systems, the XMCD spectra in the near-edge region are well reproduced. The possibility to separate the local effects from those due to the neighboring atoms in the XMCD cross section makes possible a more physical understanding of the spectra. The present results emphasize the major role played by the d states of the Tb ions in the XMCD spectrum at the Co K edge in the TbCo 5 compound.