Abstract
Spin-resolved scanning tunneling spectroscopy measurements at low temperatures were performed for Co nanostructures on . On Co monolayer islands and wires the electronic structure changes on the scale of a few atoms due to the changing local stacking of the Co atoms. First-principles calculations for pseudomorphic fcc and hcp stacked Co monolayers assign the dominant feature in the measured spectra to a -like surface resonance of minority-spin character which shifts in energy because of a different coupling to the Pt substrate. Despite the heterogeneous electronic structure of the Co monolayer, the out-of-plane magnetized domains are clearly observed. While the domain wall width measured on wires is less than there is no indication for a change in the magnetization direction for islands with a base length up to fifteen times the domain wall width. Furthermore, the magnetic hysteresis in an ensemble of out-of-plane magnetized Co monolayer as well as double-layer nanostructures was observed. While the coercivity for the monolayer nanostructures is about , double-layer islands show surprisingly large coercivities of more than .
- Received 23 June 2006
DOI:https://doi.org/10.1103/PhysRevB.74.195411
©2006 American Physical Society