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

Abstract

<p>We investigate the x-ray magnetic circular dichroism (XMCD) at the <em>L</em>_3,2 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 (<em>E</em>1: 2<em>p</em>→5<em>d</em>) and quadrupolar (<em>E</em>2: 2<em>p</em>→4<em>f</em>) transitions. On the basis of <em>ab initio</em> 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 4<em>f</em> and 5<em>d</em> moments.</p>