We provide evidence that high-pressure high-temperature (2.5 GPa and 1040 K) treatment of mixtures of iron with fullerene powders leads to the complete transformation of iron into iron carbide Fe3C. The comparison of the magnetic properties (Curie temperature and magnetic moment) of the here studied samples and those for the ferromagnetic polymer Rh-C60 indicates that the main ferromagnetic signal reported in those samples is due to Fe3C and not related to the ferromagnetism of carbon as originally interpreted. Taking into account the results obtained in this study the original paper on ``Magnetic carbon" (Nature {\bf 413}, 716 (2001)) was recently retracted.
@article{arxiv.cond-mat/0602306,
title = {Magnetic properties of polymerized C$_{60}$ with Fe},
author = {A. Talyzin and A. Dzwilewski and L. Dubrovinsky and A. Setzer and P. Esquinazi},
journal= {arXiv preprint arXiv:cond-mat/0602306},
year = {2015}
}