Strong Fano effect in the magnetic circular dichroism of the Pt N6,7 core absorption of ferromagnetic CoPt3

We report the core photoabsorption (XAS) and magnetic circular dichroism (MCD) spectra in the Pt N{sub 6,7}(4f{r_arrow}5d) region of the ferromagnetic CoPt{sub 3}. The measured XAS spectra have shown typical Fano line shapes, and the MCD spectrum has shown very unusual features that cannot be explained within the framework of the conventional selection rule for the dipole transition. It is revealed from a theoretical analysis that the strong Fano effect is essential to interpret these MCD features. We will discuss in detail the influence of the Fano effect on the Pt N{sub 6,7} MCD line shape. {copyright} {ital 1997} {ital The American Physical Society}