Size and stoichiometry-dependent magnetic properties of deposited Co and CoPt alloy clusters on a Ni/Cu(100) substrate have been investigated by use of x-ray magnetic circular dichroism spectroscopy. Using sum rules, spin and orbital moments were extracted from the spectra. Spin and orbital moments show a strong size-dependent effect with a tendency for an increase with cluster size, which is in contrast to observations for Co clusters on a Pt(111) surface. Addition of a Pt atom to a Co dimer leads to a doubling of the orbital moment. CoPt clusters show a strong increase in chemical reactivity towards oxidation. The resulting Co n PtO x clusters show a ratio of orbital to spin moment comparable to the pure clusters, however, with a strong suppression of the absolute orbital and spin moments.
Ultrasmall magnetic clusters and adatoms are of strong current interest because of their possible use in future technological applications. Here, we demonstrate that the magnetic coupling between the adsorbates and the substrate can be significantly changed through oxidation. The magnetic properties of Co adatoms and CoPd dimers deposited on a remanently magnetized Ni/Cu(100) substrate have been investigated by x-ray absorption and x-ray magnetic circular dichroism spectroscopy at the Co L 2,3 edges. Using spectral differences, pure and oxidized components are distinguished, and their respective magnetic moments are determined. The Co adatoms and the CoPd dimers are coupled ferromagnetically to the substrate, while their oxides, Co-O and CoPd-O, are coupled antiferromagnetically to the substrate. Along with the spin reorientation from the pure to the oxidized state, the magnetic moment of the adatom is highly reduced from Co to Co-O. In contrast, the magnetic moment of the dimer is of similar order for CoPd and CoPd-O.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.