Abstract
Carbon nanotubes（CNTs）are graphene sheets rolled up into cylindrical structure and electron transport via tube surface lattice is essentially isotropic. This description is based on a 2D lattice model. In a 3D approach, electron wave function near to the Fermi level is extended by 1 Å along the 2Pz orbit and electron transport thus becomes sensitive to electron field. Reports indicate two possible paths of charge carrier in a small CNT, i.e. along tube axis and circumference. When electric field is applied in parallel with tube axis the electron flux along circumference is diverted into a helix current, similar to nano-coils. This spiral current becomes apparent when angular frequency is smaller than stark frequency in an AC field. To date, explore of magnetic field within a CNT remains as challenge and a straightforward verification is to encapsulate magnetic materials in CNTs so interior magnetic field is enhanced and becomes measurable. In this work, individual Fe-encapsulated CNTs bridging tungsten electrodes are verified and measured by AC impedance technique. Inductance at different frequency is detected and is on the order of mH.