Controlling flux flow dissipation by changing flux pinning in superconducting films

摘要

We study the flux flow state in superconducting materials characterized by rather strong intrinsicpinning, such as Nb, NbN, and nanostructured Al thin films, in which we drag the superconductingdissipative state into the normal state by current biasing. We modify the vortex pinning strengtheither by ion irradiation, by tuning the measuring temperature or by including artificial pinningcenters. We measure critical flux flow voltages for all materials and the same effect is observed:switching to low flux flow dissipations at low fields for an intermediate pinning regime. Thismechanism offers a way to additionally promote the stability of the superconducting state.