Circular magnetic x-ray dichroism in rare earth compounds.

摘要

Circular magnetic x-ray dichroism (CMXD) has been used to probe the magnetic properties of rare earth compounds. This study has been undertaken in two distinct parts. First, the angular dependence of the CMXD signal has been examined in order to determine the multiple nature of the transitions involved. Second, the nature of the dichroic spectra of amorphous and crystalline GdFe;Previous CMXD measurements at the L edges of rare earth materials have demonstrated two distinct features, one above and one below the Fermi energy. Theoretical calculations have ascribed the two features to dipolar and quadrupolar transitions to the empty 5d and 4f states respectively. This study sought to determine the multipole nature of the transitions involved by measuring the angular dependence of the CMXD signal. Two experiments attempting to observe this angular dependence were undertaken, one at the L;The spin dependent absorption of circularly polarized x-rays at the K edge of Fe and the L