Electron holography of single-crystal iron nanorods encapsulated in carbon nanotubes Available to Purchase

$α-Fe$ nanorods encapsulated in multiwall carbon nanotubes (CNTs) were characterized by x-ray diffraction (XRD), high resolution electron microscopy (HREM), and electron holography. HREM observations revealed that the $α-Fe$ nanoparticles were single crystals with a preferential growth direction of $⟨200⟩α-Fe$ oriented along CNTs. Phase distributions of an $α-Fe$ nanorod were measured by electron holography and the remanent state was retrieved by a three-dimensional morphological model and an algorithm with the consideration of irregular nanoparticle shape. It was found that the saturated magnetization of the $α-Fe$ nanorod with a CNT outer shell was very close to that of bulk pure $α-Fe$⁠, suggesting that the core-shell nanostructure effectively prevented the surface oxidation that had been found to significantly degrade the magnetic properties of nanostructured $α-Fe$⁠.