Magnetostrictive friction of graphene sheets embedded carbon film

We report a magnetostrictive friction phenomenon in atomic force microscopy (AFM) silicon probe sliding against graphene sheets embedded carbon (GSEC) film under external magnetic field. A special electromagnet device was designed on AFM to generate controllable magnetic field for the magnetostrictive friction measurements. GSEC films possessing self-magnetism were prepared by electron irradiation in electron cyclotron resonance (ECR) plasma. The magnetostrictive friction was investigated by adjusting the external magnetic field intensity and self-magnetism of the film. The results showed that the presence of the magnetic field resulted in an evident increment of the friction force of GSEC films with different magnetism, while the friction of nonmagnetic silicon wafer was not affected, indicating that the interaction between external magnetic field and the self-magnetism of the carbon film contributes to the friction increment, i.e. magnetostrictive friction. The mechanism of the magnetostrictive friction was ascribed to the atomic scale real contact area increment induced by the magnetostrictive strain of the graphene sheets. This finding may shed light on the new applications of magnetostrictive friction of carbon film.