  We report a density-functional study of the heteronuclear CoIr dimer adsorbed
on benzene or graphene. In either case CoIr prefers an upright position above
the center of a carbon hexagon with the Co atom next to it. The Ir atom stays
away from the carbon ring and thus preserves its free-atom-like properties.
This results in a very large magnetic anisotropy of more than 0.2 eV per dimer.
So high a value should suffice for long-term data storage at the temperature of
liquid nitrogen.

Mesoscale and Nanoscale Physics