Structure and magnetism of hcp(0001) and fcc(001) thin cobalt films on a clean and carbon-reconstructed W(110) surface

The morphology of cobalt films on W(110) depends on the cleanness of the surface. Epitaxial hcp(0001) films are formed on a clean surface whereas the fcc(001) structure is observed in case of a carbon-induced reconstruction of the tungsten surface. Here, fcc cobalt films with two different domains are investigated with LEED and STM concerning details of their growth. Furthermore, the electronic structure of these films is studied with angle resolved valence band photoelectron spectroscopy using circularly polarized VUV synchrotron radiation. Additionally, intensity differences in the photoelectron spectra are obtained when reversing the magnetization directions giving access to the magnetic properties via the phenomenon of magnetic circular dichroism in the angular distribution of photoelectrons (MCDAD). The results are compared with those for hcp cobalt films.