Electromigration-driven linear actuator operations of Co nanorods inside and outside multi-walled carbon nanotubes with stroke of tens of nanometers.

Solid Co nanorod fillers were pushed out of multi-walled carbon nanotubes via electromigration and their behaviors were observed in situ by transmission electron microscopy. When a solid Co nanorod was pushed out, the portion outside the nanotube increased in diameter. The behavior of the plastic deformation depended on the crystal orientation of the Co nanorod filler. When the direction of the electron flow was reversed, the Co nanorod was pulled into the host nanotube. In one trial, the Co nanorod was split into two portions inside the nanotube near one of the electrodes.