Applications of soft X-ray magnetic circular dichroism

Several recent examples of the application of soft X-ray magnetic circular dichroism (SX-MCD) in the study of magnetic systems are presented. First, the applicability and limitations of obtaining element-specific orbital and spin moments in magnetic systems via transmission MCD method are described. As an extension of this method, spin polarized L-edge extended X-ray absorption fine structure (EXAFS) of Fe, Co, and Ni films are measured. The data show the presence of a large spin dependence in the EXAFS of Fe and Co while no measurable dependence is seen for Ni, indicating significant differences between the spin-dependent scattering potentials of Fe, Co, and Ni. To further demonstrate the applicability of SX-MCD to practical systems, two dimensional magnetic hysteresis loops of a complicated trilayer system, FeCo/Mn/FeCo, are measured for each of the constituent elements. The data indicate that Mn has a net moment in this system and is strongly coupled to the enclosing FeCo layers. Furthermore, the results show unequivocally that the Mn moment is rotated from that of Fe and Co by -23° and this angle is largely preserved throughout the moment reversal process