High-pressure behaviour of Ni-filled and Fe-filled multiwalled carbon nanotubes

Abstract

The high-pressure behavior of Ni-filled and Fe-filled multiwalled carbon nanotubes has been investigated up to 27 GPa and 19 GPa, respectively, with the help of synchrotron-based angle-dispersive X-ray diffraction. These nanotubes do not show any structural transformation up to the highest pressures studied. These results are similar to that of Co-filled nanotubes [1], but are in sharp contrast to the earlier results on Fe-filled tubes [2], where the tubes were found to undergo a sudden collapse of intertube separation. Our present observations suggest that the occurrence of an isostructural phase transition in Fe3C, observed in our earlier study, may be responsible for the structural transition in nanotubes in that case.