We present a study of the structure of Co/W(001) determined by low-energy e
lectron diffraction, the film stress measured by a bending thin substrate,
and the film morphology measured by scanning tunneling microscopy in combin
ation with in situ magnetic characterization by the magneto-optic Kerr effe
ct. Different regimes in the stress behavior during growth are correlated t
o surface effects and structural and morphological changes in the Co film.
Initially a compressive stress is observed as the result of the lower surfa
ce free energy of Co compared to W, followed by a tensile stress due to the
large misfit between film and substrate. The structural transition from bc
c to hcp Co as well as dislocation formation is clearly observed in the str
ess measurements and by low-energy electron diffraction and scanning tunnel
ing microscopy. Additionally, the morphology of the films is correlated wit
h the magnetic properties and a new surface alloy at submonolayer coverages
is reported.