Orbital and spin magnetic moments of transforming one-dimensional iron inside metallic and semiconducting carbon nanotubes

Abstract

The orbital and spin magnetic properties of iron inside metallic and semiconducting carbon nanotubes are studied by means of local x-ray magnetic circular dichroism (XMCD) and bulk superconducting quantum interference device (SQUID). The iron-nanotube hybrids are initially ferrocene filled single-walled carbon nanotubes (SWCNT) of different metallicities. We show that the ferrocene's molecular orbitals interact differently with the SWCNT of different metallicities with no significant XMCD response. At elevated temperatures the ferrocene molecules react with each other to form cementite nanoclusters. The XMCD at various magnetic fields reveal that the orbital and/or spin magnetic moments of the encapsulated iron are altered drastically as the transformation to the 1D clusters 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 polarization of the encapsulated material depends 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 dominate the magnetic properties of these 1D hybrid nanostructures.

Nickel clusters embedded in carbon nanotubes as high performance magnets

“…In this contribution we report a neat method for magnetic nanostructuring within a single-wall carbon nanotube (SWCNT) 12 13 14 15 16 17 18 , that is an advanced conductor with tunable metallicity 19 20 . Ensembles of fcc nickel nano clusters have been produced in designer mean dimensions inside SWCNT bundles.…”

Structural, electronic and magnetic properties of chiral nanotubes filled with a linear chain of iron

“…At the same time, the experimental studies of encapsulation inside single-walled nanotubes are rather scarce. 11,12 The situation is opposite for theoretical studies. Most ab initio calculations of electronic and magnetic properties were conducted for singlewalled carbon NT filled with transition metal nanowires.…”

“…[13][14][15][16][17][18][19][20][21] Using NTþTM as memory elements for magnetic recording implies sufficient internal anisotropy. However, several experimental magnetization studies 6,12 have shown that NTþTM exhibit superparamagnetic behavior, which is unsuitable for memory elements. One of the reasons for this behavior is that the existing technologies for filling NT with metal result in the formation of metal clusters within the nanotube, which consist of several tens of atoms and are separated from each other.…”

Exchange coupling in a frustrated trimetric molecular magnet reversed by a 1D nano-confinement

“…The magnetisation per nickel atom has been evaluated by taking the nickel atomic concentration derived from the XPS data into account (see ESI, section 4 †). 27 The magnetisation curves are linear at magnetic fields up to ±0.7 T for 3D-Ni(acac) 2 , ±0.8 T for 1D-Ni (acac) 2 @NT2.1 and ±0.9 T for 1D-Ni(acac) 2 @NT1.3 so that according to the Curie law we can calculate the effective…”