The impact of structural relaxation on spin polarization and magnetization reversal of individual nano structures studied by spin-polarized scanning tunneling microscopy

Abstract

The application of low temperature spin-polarized scanning tunneling microscopy and spectroscopy in magnetic fields for the quantitative characterization of spin polarization, magnetization reversal and magnetic anisotropy of individual nano structures is reviewed. We find that structural relaxation, spin polarization and magnetic anisotropy vary on the nm scale near the border of a bilayer Co island on Cu(1 1 1). This relaxation is lifted by perimetric decoration with Fe. We discuss the role of spatial variations of the spin-dependent electronic properties within and at the edge of a single nano structure for its magnetic properties.

Effect of mesoscopic misfit on growth, morphology, electronic properties and magnetism of nanostructures at metallic surfaces

“…We are led to the proposition that structural relaxation at the island edge is a pivotal aspect of this peculiar behavior. This view is corroborated by our recent experiments which indicate a lifting of structural relaxation upon perimetric decoration of the Co islands with a bilayer Fe stripe [131]. As a result, now all atoms of the Co core show a magnetic anisotropy.…”

“…Our quantitative analysis of magnetization reversal data by spin-STM provide compelling evidence that the atoms near the edge of the Co bilayer island are magnetically soft, i.e. they exhibit a vanishing magnetic anisotropy [69,71,131]. We are led to the proposition that structural relaxation at the island edge is a pivotal aspect of this peculiar behavior.…”

“…Here we exploit the spatial resolution of the STM to investigate the position dependence of the differential conductance signal [130,131] within pure and Fe-decorated Co islands. These data provide compelling evidence that structural relaxations in the Co core are lifted upon decoration.…”

Spin-polarized scanning tunneling microscopy with quantitative insights into magnetic probes

“…The experiments were performed in situ in an ultra-high vacuum (UHV) chamber (base pressure <1 × 10 −11 mbar) equipped with a liquid He cooled scanning tunneling microscope operating at 10–30 K and a superconducting magnet for field of up to 7 T normal to the sample surface [4, 18]. …”

“…Here we focus on biatomic-layer-high (BLH) Co, Fe, and Fe-decorated Co (Fe|Co) islands on Cu(111) [7, 18–20]. Figure 2a schematically illustrates the sample preparation procedure.…”