Current crowding effects in superconducting corner-shaped Al microstrips

Abstract

The superconducting critical current of corner-shaped Al superconducting microstrips has been investigated. We demonstrate that the sharp turns lead to asymmetric vortex dynamics, allowing for easier penetration from the inner concave angle than from the outer convex angle. This effect is evidenced by a rectification of the voltage signal otherwise absent in straight superconducting strips. At low magnetic fields, an enhancement of the critical current with increasing magnetic field is observed for a particular combination of field and current polarity, confirming a theoretically predicted competing interplay of superconducting screening currents and applied currents at the inner side of the turn.