Graphene is expected to complement todays Si-based information technology. In particular, magnetic molecules in contact with graphene constitute a tantalizing approach towards organic spin electronics because of the reduced conductivity mismatch at the interface. In such a system a bit is represented by a single molecular magnetic moment, which must be stabilized against thermal fluctuations. Here, we show in a combined experimental and theoretical study that the moments of paramagnetic Co-octaethylporphyrin (CoOEP) molecules on graphene can be aligned by a remarkable antiferromagnetic coupling to a Ni substrate underneath the graphene. This coupling is mediated via the \pi\ electronic system of graphene, while no covalent bonds between the molecule and the substrate are established.
@article{arxiv.1304.4755,
title = {Magnetic coupling of porphyrin molecules through graphene},
author = {C. F. Hermanns and K. Tarafder and M. Bernien and A. Krüger and Y. -M. Chang and P. M. Oppeneer and W. Kuch},
journal= {arXiv preprint arXiv:1304.4755},
year = {2013}
}