Phase transformations in pressure polymerized C60

Korobov, M.V.; Senyavin, V. M.; Bogachev, A. G.; Stukalin, Evgeny B.; Davydov, V. A.; Kashevarova, L. S.; Rakhmanina, A. V.; Агафонов, В.; Szwarc, A.

doi:10.1016/j.cplett.2003.10.011

Cited by 31 publications

(7 citation statements)

References 15 publications

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“…In conclusion, the cage distortion of C 60 in polymerized 2D-plane Rh-C 60 leads to competition between diamagnetic and ferromagnetic states, with the ferromagnetic state populated by thermal excitation. Recently, several experimental and theoretical studies on Rh-C 60 polymers and related carbon systems have been reported [19][20][21][22][23][24][25][26][27]. Some of them support previous results by Makarova et al The present results provide one possible explanation of these results.…”

Section: Discussionsupporting

confidence: 82%

Theoretical Studies on Electronic States of Rh-C60. Possibility of a Room-temperature Organic Ferromagnet

et al. 2004

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Abstract:A possible mechanism for a ferromagnetic interaction in the rhombic (Rh) form of C 60 (Rh-C 60 ) is suggested on the basis of theoretical studies in relation to cage distortion of the C 60 unit in the polymerized 2D-plane. Band structure calculations on Rh-C 60 show that cage distortion leads to competition between diamagnetic and ferromagnetic states, which give rise to the possibility of thermally populating the ferromagnetic state.

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Section: Discussionsupporting

confidence: 82%

Theoretical Studies on Electronic States of Rh-C60. Possibility of a Room-temperature Organic Ferromagnet

et al. 2004

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“…27 The ferromagnetism of "magnetic carbon" was preserved after heating up to 640 K for two hours 2 and even after heat treatment at 800 K for several hours 8 which means that the polymeric structure was not anymore present in the samples after the first heating run and therefore responsible for the observed ferromagnetism. We note that some samples of the "magnetic carbon" species of the first publication were studied later and depolymerized as expected below 600 K. 28 Moreover, the same set of samples as in ref. 2 was tested in an earlier study and was reported to depolymerize completely at 473 K. 29 Finally, the recently published corrigendum 30 confirmed that one of the two samples which ever showed 500 K Curie temperature was synthesized at 2.5 GPa and 1125 K. The temperature of 1125 K is well above the point of C 60 collapse.…”

Section: Discussionmentioning

confidence: 82%

Structural and magnetic properties of polymerized C60 with Fe

et al. 2007

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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 413, 716 (2001)) was recently retracted.

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“…Such a reaction should occur especially easily for the C-C bonds connecting fullerene molecules because those bonds are less stable than the C-C bonds in the C 60 cage. For example, atmospheric pressure depolymerization of HPHT polymers occurs at 500-550 K, [42,43] whereas reaction of hydrogen gas with solid C 60 starts only at $625 K [26]. Therefore, hydrogenation of polymers should result in destruction of the polymeric structure.…”

Section: Discussionmentioning

confidence: 99%