Magnetic properties of nanostructures

Pt-supported Co nanomagnets
(Adriano Mosca Conte, Stefano Fabris, and Stefano Baroni)

We investigate the electronic, structural, and magnetic properties of Co-based low-dimensional nanostructures supported by Pt surfaces by using computer simulations based on density functional theory (DFT). The effects of the local orientation of the magnetization, including the magnetic anisotropy energy (MAE), are accounted for within a non-collinear spin DFT formalism where the spin-orbit interaction is described by fully relativistic ultrasoft pseudopotentials. Our study shows that the magnetic moments, the direction of the easy-magnetization axis, and the MAE are extremely sensitive on the local atomic environment around the supported Co adatoms. These results have general implications on the possibility of tailoring the magnetic properties of low dimensional structures by engineering the local environment of the magnetic centers.

Adriano Mosca Conte
Quantum mechanical modeling of nano magnetism: new tools based on Density-Functional theory with case applications to solids, surfaces, wires, and molecules
PhD Thesis, SISSA (2007)

Adriano Mosca Conte, Stefano Fabris, and Stefano Baroni
Properties of Pt-supported Co nanomagnets from relativistic DFT calculations
submitted

Ab-initio investigations of surface magnetism and dichroism spectra
(Natasa Stojic and Nadia Binggeli)

With reducing dimensionality, many nonmagnetic materials show a tendency towards magnetism. Apart from the interest stemming from the technological perspective (magnetic films, multilayers, etc), studies on such systems may result in an understanding reaching the origins of magnetism. We investigate surface magnetism of two completely different metals, Rh and U, as examples of the lower rows of the transition metal group and the actinides, respectively. In particular, the study of the Rh(100) surface has been motivated by measurements of the linear-magnetic dichroism of the Rh 3d electrons by the Elettra SuperESCA group: it is the only nonmagnetic elemental metal that features an experimentally observed surface magnetic moment.

N. Stojić, N. Binggeli, and M. Altarelli
Surface magnetism of Rh(001) from LDA+U calculations
Phys. Rev. B 73, 100405(R) (2006)

Surface-supported single molecular magnets
(Adriano Mosca Conte, Stefano Fabris, and Stefano Baroni)

The miniaturization of information storage devices drives the search for new nano-scale magnetic materials. Single molecular magnets formed by metal-organic complexes are very promising candidates because of their large spin ground state, large magnetic anisotropy, and weak intermolecular interactions. Moreover, these systems provide a natural playground to explore magnetism at the nanoscale. We investigate the electronic and magnetic properties of novel single-molecular-magnets supported by metal surfaces with density functional theory and scanning tunneling spectroscopy. These studies reveal that the interaction with the metal surface can preserve both the molecular structure and the large spin magnetic moment of the magnetic center.

In collaboration with:

  • Max-Planck Institute fuer Festkoerperforschung (L. Vitali and K. Kern)
  • Research Center Karlsruhe (K. Ruben)