Spin resolved vacant state spectroscopy by means of x-ray resonance magnetic scattering (invited) (abstract)

Abstract

X-ray resonance magnetic scattering (XRMS) is a combined effect of a spin-dependent electromagnetic interaction and a spin polarization of the intermediate state in resonance. The first observation of XRMS, which was performed by the present author and his co-workers, was concerned with Ni K-shell electrons. Information derived from that experiment was therefore restricted to the polarization of the p-type density of states above the Fermi level. In the present work, however, XRMS from Gd has been observed near the L absorption edge. The spin polarization spectrum relevant to the unoccupied d-type density of states has also been investigated. Owing to a high value of d-band density of states and its high polarization and also to large value of atomic scattering factor, the asymmetrical ratio of XRMS, (I↑−I↓)/(I↑+I↓), amounts to several percent at the maximum by contrast with the value of 1×10−3 for the case of Ni. The majority spin of Gd d band is found to be in excess at approximately 2 eV above the Fermi level and the minority spin in excess at approximately 8 eV above the Fermi level. The results derived from XRMS are compared with the results of a band theory calculation. Both temperature and magnetic field dependencies of the asymmetrical ratio are also discussed.