Orbital and spin magnetic moments of transforming 1D iron inside metallic and semiconducting carbon nanotubes

TL;DR

This study investigates how the orbital and spin magnetic moments of iron inside 1D carbon nanotube hybrids change during transformation from ferrocene to iron nanoclusters, revealing dependence on nanotube metallicity and delocalized magnetism.

Contribution

It provides new insights into the magnetic behavior of iron nanoclusters inside carbon nanotubes and how metallicity influences their magnetic moments during transformation.

Findings

Magnetic moments are larger in semiconducting nanotubes than in metallic ones.

Iron magnetic properties are significantly altered during nanocluster formation.

Delocalized magnetism governs the overall magnetic behavior of the nanostructures.

Abstract

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.