A novel type of iron–carbon composite nano-structures has been synthesised from a pressurized ferrocene vapor. Scanning electron microscopy shows that the nano-structures are produced in large yield and high purity. Their unique morphology is manifested by high reflectional symmetry, composed of two conical arms spiralling out of an almost spherical core. The size extends to 40m in length with the arm's tips as thin as 100 nm.
In the micrograph, the core area shows brighter contrasts than the arms, indicating its iron richness. Micro-Raman spectroscopy across the sample surface unravels that the graphitic arms encapsulate the iron core entirely. Such unique encapsulated nano-composites with defined shapes could be useful in many applications.