Theoretical analysis of X-ray magnetic circular dichroism at the Yb L2, 3 absorption edges of YbInCu4 in high magnetic fields around the field-induced valence transition

High-magnetic-field X-ray absorption spectra (XAS) and its X-ray magnetic circular dichroism (XMCD) at the Yb L-2,L- 3 edges of YbInCu4 are calculated around the field-induced valence transition at about 30 T. The calculations are made by using a new theoretical framework with an extended single impurity Anderson model (SIAM) developed recently by the present author. Two parameters in SIAM, the 4f level and the hybridization strength, are taken as different values in low-and high-magnetic-field phases of the field-induced valence transition. The calculated results are compared with recent experimental data measured by Matsuda et al. by utilizing a miniature pulsed magnet up to 40 T. The field-dependence of the calculated XMCD spectra is explained in detail on the basis of the field-dependence of the Yb 4f wavefunctions in the ground state. Some possibilities are discussed on the negative XMCD signal observed experimentally at the L-2 edge.