Chemisorption-induced change in thin-film spin anisotropy: Oxygen adsorption on the p(1 x 1)Fe/Ag(100) system

Misfit-induced modification of structure and magnetism in O/Fe(001)-p(1×1)

The geometry of oxygen atoms in hollow sites of Fe nanoislands (⊘≈1-2  nm) on Fe(001) is modified by mesoscopic misfit-induced relaxations of the island atoms. Surface x-ray diffraction, scanning tunneling microscopy, and ab initio calculations indicate a 0.3 Å increased adsorption height [0.7 Å versus 0.4 Å in O/Fe(001)-p(1×1)] of O atoms going in parallel with a reduced Fe-Fe layer spacing inducing a reduction of the surface magnetic moment (2.85μ(B) versus 3.2μ(B)). Our results demonstrate the importance of the mesoscopic misfit for surface physical properties in general.

Surface magnetism during oxygen-aided Fe homoepitaxy

Magnetization-induced optical surface second harmonic generation (SHG) in the longitudinal geometry was used to study magnetism on the p(1 x 1)O/Fe(001) surface during a layer-by-layer Fe growth with surfactant oxygen. Considerable one-monolayer oscillations were observed. Minima of the magnetization-induced contributions to the second order dielectric susceptibility were detected at half-filled monolayers. These contributions were accessed either by measuring a purely magnetic SHG yield, or indirectly from the magnetization dependence of the overall SHG signal, both providing consistent results. The origin of the oscillatory surface magnetism is consistent with the expected oscillating oxygen induced relaxation due to the surface Fe islands.