A single Co atom adsorbed on Cu(111) or on ferromagnetic Co islands is contacted with non-magnetic W or ferromagnetic Ni tips in a scanning tunneling microscope. When the Co atom bridges two non-magnetic electrodes conductances of 2e^2/h are found. With two ferromagnetic electrodes a conductance of e^2/h is observed which may indicate fully spin-polarized transport.
@article{arxiv.0809.3567,
title = {Quantized Conductance of a Single Magnetic Atom},
author = {N. Neel and J. Kroeger and R. Berndt},
journal= {arXiv preprint arXiv:0809.3567},
year = {2009}
}