Theoretical investigation of near-edge phenomena in magnetic systems

摘要

Theoretical results on x-ray resonant magnetic scattering at the M$-4,5$/-edges of Uranium compounds and circular magnetic x-ray dichroism at the L$-3$/-edge of heavy rare earth systems are reported, with the aim of providing an interpretation of recent experiments. Near an inner-shell absorption threshold, the effect of spin-orbit and exchange interactions is reflected in the presence of magnetization-sensitive components in the anomalous scattering amplitude; as a consequence, x-ray magnetic scattering can exhibit a dramatic enhancement. This has been demonstrated experimentally and theoretically. In the x-ray region, strong magnetic effects can be observed in absorption (linear and circular dichroism), the Kerr effect, and Faraday rotation. Dispersive and absorptive processes are determined by the forward scattering amplitude; hence, the above-mentioned magneto-optical phenomena can be brought together into a general formulation. Recently, magnetization-sensitive effects, associated with x-ray photoemission, have also been observed and discussed. In this paper we report ab initio atomic calculation of resonant magnetic scattering (XRES) at the M$-4,5$/-edges of the Uranium compounds. Also, we present calculations of circular magnetic x-ray dichroism at the L$-3$/-edge of the Gd$YLD@Tm series.