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.
@article{arxiv.1010.5663,
title = {CoIr-carbon complexes with magnetic anisotropies larger than 0.2 eV: a density-functional-theory prediction},
author = {Ruijuan Xiao and Michael D. Kuz'min and Klaus Koepernik and Manuel Richter},
journal= {arXiv preprint arXiv:1010.5663},
year = {2015}
}