Magnetic x-ray circular dichroism in photoelectron spectroscopy and diffraction

In this paper, we discuss a series of photoelectron-spectroscopy (PS) and photoelectron-diffraction (PD) studies utilizing magnetic x-ray circular dichroism and fully spin-specific, multiple-scattering calculations for analysis of the experimental results. The test system used was perpendicularly magnetized, ferromagnetic monolayer Fe/Cu(001), prepared and probed at low temperature. Two sets of states were used: the Fe2p at binding energies of over 700 eV (large spin-orbit and small exchange splittings) and the Fe3p at a binding energy of near 53 eV (spin-orbit and exchange splittings approximately equal). The PS and PD measurements made were angularly resolving and compared to calculational results which were similarly angularly dependent. Both ''exchange shifts'' and intensity variations of spectral structure were observed. The impact of ''j-state mixing'' was seen in both the Fe2p and 3p spectra. Our results indicate a ferromagnetically ordered FCC Fe with a lattice parameter near that of bulk Cu. Nevertheless, the sensitivity of the multiple-scattering calculations of both the Fe2p and Fe3p simulations to local order has been used to show that the overlayer structure posseses some level of imperfection or disorder as well.