The filling of carbon nanotubes with magnetoelectric Cr2O3

We report the encapsulation of the antiferromagnetic and magnetoelectric oxide Cr2O3 inside both multi - and single-walled carbon nanotubes. This is achieved by a two step post-synthesis filling process which involves the filling of nanotubes with CrO3 either from aqueous solution or from the molten phase, followed by appropriate annealing sequences. TEM imaging confirms significant filling rates for both multi- and single-walled carbon nanotubes. Analytical transmission electron microscopy implies that after secondary annealing Cr2O3 is formed inside the nanotubes.