Controlled pinning on vanadium strips during diffusion implantation of gases

A study has been made of the changes which occur in the critical currents and current-voltage characteristics of vanadium foil as a consequence of implantation of gas into the surface of the specimen by diffusion. It is shown that this leads to a change in the condition for the penetration of vortices into the superconductor because of their being pinned in the surface layer as well as a change in the critical currents. Possible mechanisms of pentration of magnetic flux are discussed for the case of low and high magnetic fields