Theoretical study of iron-filled carbon nanotubes
Résumé
The structural arrangements and magnetic properties of iron encapsulated in single wall carbon nanotubes (SWCNT) are investigated. Fe nanowires are of interest because of their potential use in spintronics. They have also been fabricated inside carbon nanotubes, where occasionally exchange bias has also beendetected. An additional motivation to study these systems is to contribute to the understanding of how the iron-carbon interactiondetermines the magnetic ordering. Here we investigate, using ab-initio methods,the geometry and magnetic structure of freestanding and encapsulated Fe nanowires. In addition, we also investigate the energetics and magnetic properties of the nanowire-nanotube system when defects are present in the single wallcarbon nanotube. When the ratio of the nanowire to nanotube diameter is small the system is stable and the spin polarization at the Fermienergy is large, thus making the system potentially interesting for spintronics. When this ratio is close to one the system is lessstable and a tendency towards antiferromagnetic ordering is occasionally observed.