  The orbital and spin magnetic properties of iron inside transforming metallic
and semiconducting 1D carbon nanotube hybrids are studied by means of local
x-ray magnetic circular dichroism (XMCD) and bulk superconducting quantum
interference device (SQUID) measurements. Nanotube hybrids are initially
ferrocene filled single-walled carbon nanotubes (SWCNT) of different
metallicities. After a high temperature nanochemical reaction ferrocene
molecules react with each other to form iron nano clusters. We show that the
ferrocenes molecular orbitals interact differently with the SWCNT of different
metallicities without significant XMCD response. This XMCD at various
temperatures and magnetic fields reveals that the orbital and/or spin magnetic
moments of the encapsulated iron are altered drastically as the transformation
to 1D Fe nanoclusters takes place. The orbital and spin magnetic moments are
both found to be larger in filled semiconducting nanotubes than in the metallic
sample. This could mean that the magnetic polarizations of the encapsulated
material is dependent on the metallicity of the tubes. From a comparison
between the iron 3d magnetic moments and the bulk magnetism measured by SQUID,
we conclude that the delocalized magnetisms dictate the magnetic properties of
these 1D hybrid nanostructures.
