The polarization of Sb overlayers on NiMnSb(100)

We have investigated the induced polarization of paramagnetic Sb overlayers on the Heusler alloy NiMnSb. From combined X-ray absorption spectroscopy ( XAS) and spin-polarized inverse photoemission spectroscopy (SPIPES), we can assign some of the unoccupied states of the Heusler alloy NiMnSb. With inc reasing thickness of the Sb overlayer, there is a decline in the density of states near the Fermi energy, as expected for a semimetal overlayer on a m etallic substrate. While the Sb is polarized by the ferromagnetic NiMnSb su bstrate, consistent with the expectations of mean field theory, the polariz ation at the center of the surface/overlayer Brillouin zone cannot be easil y related to the induced magnetization. (C) 2000 Elsevier Science B.V. All rights reserved.