Record breaking magnetic anisotropy energy

Large magnetic anisotropy energy (MAE) is desirable and critical for nanoscale magnetic devices. In this talk, using ligand-field level diagrams and density functional calculations, we first shed light on the very recent discovery [I. G. Rau et al., Science 344, 988 (2014)] that an individual Co adatom on a MgO (001) surface has a large MAE of more than 60 meV. Then, more importantly, we predict that a giant MAE up to 110 meV could be achieved for a single Ru adatom on MgO (001), and even more for a single Os adatom (208 meV). This is a joint effect of the special ligand field, orbital multiplet, and significant spin-orbit interaction, in the intermediate-spin state of the Ru or Os adatom on top of the surface oxygens. The record breaking MAE could provide a route to atomic scale memory.Ref: Xuedong Ou, Hongbo Wang et al., PRL in press (2015).