T. L. Makarova-Nature 2001

This paper was retracted on 30 March 2006 Nature 440, 707, 2006.
Retraction Reason:
In this Letter we reported high-temperature ferromagnetism in a polymeric phase of pure carbon that was purportedly free of ferromagnetic impurities1. Since then, however, measurements made on the same and similar samples using particle-induced X-ray emission (PIXE) with a proton microbeam have indicated that these had considerable iron content. Also, polymerized C60 samples mixed with iron before polymerization had a similar Curie temperature (500 K) to those we described1, owing to the presence of the compound Fe3C (cementite). In addition, it has since been shown that the pure rhombohedral C60 phase is not ferromagnetic.
Nevertheless, magnetic order in impurity-free graphitic structures at room temperature has been demonstrated independently(before and after publication of ref. 1). Ferromagnetic properties may yet be found in polymerized states of C60 with different structural defects and light-element (H, O, B, N) content.
T.L.M. and P.S. decline to sign this retraction because they do not believe that the earlier results1, supported in subsequent studies, are totally invalidated by these findings.
Originally Published:
Nature 413, 716–718 (2001)
Title:
Magnetic carbon
Authors:
T. L. Makarova*, B. Sundqvist, R. Höhne, P. Esquinazi, Y. Kopelevich, P. Scharff, V. Davydov, L. S. Kashevarova and A. V. Rakhmanina
Affiliation:
Ioffe Physico-Technical Institute,Russia
Department of Experimental Physics, Umeå University,Sweden
Institute for Physics, Chemical Department, TU Ilmenau, Germany
Abstract: