Resonance Photoemission and Spin Polarization of Fe$_{x}$Co$_{1-x}$S$_{2}$*

The electronic structure in the region of the Fe/Co 3d band for Fe$_{x}$Co$_{1-x}$S$_{2}$ has been investigated by photoemission and spin polarized photoemission. The comparison between the results for different content of doped Fe was made, specifically x=0, 0.05, 0.10, 0.15 and 1. While the surface spin polarization of Fe$_{x}$Co$_{1-x}$S$_{2}$, measured by spin polarized ultraviolet photoemission, was reduced compared with the bulk value, we see that the spin polarization increases with Fe doping level for textured thin films. The resonance photoemission spectroscopy shows that sulfur bands have strong resonance at the photon energy of the Co 2p core level, indicating strong hybridization between Co and sulfur bands in Fe$_{x}$Co$_{1-x}$S$_{2}$ (small x) however, the ultraviolet photoelectron spectroscopy (UPS) of FeS$_{2}$ exhibits a slightly different d-band density of states than Fe$_{x}$Co$_{1-x}$S$_{2}$.