Quadrupolar and dipolar contributions to x-ray magnetic circular dichroism at the Tb L3,2 edges:: Experiment versus theory

We investigate the x-ray magnetic circular dichroism (XMCD) at the L-3,L-2 edges using a single crystal of Tb as a prototype system for a one-element magnet in order to ascertain the multipolar nature of the features in the dichroic spectra. The high resolution of the experimental data allows for a clear identification of the dipolar (E1: 2p-->5d) and quadrupolar (E2: 2p-->4f) transitions. On the basis of ab initio calculations we developed a simple procedure to extract the quadrupolar part by subtracting the derivative of the spin-averaged absorption spectra from the experimental XMCD data. The deconvolution has to be carried out before applying sum rules to determine 4f and 5d moments. (C) 2002 American Institute of Physics.