Mesoscopic cross-film cryotrons: Vortex trapping and dc-Josephson-like oscillations of the critical current

TL;DR

This study explores how a control wire influences the critical current in a superconducting strip, revealing vortex trapping effects that cause oscillations in the critical current, combining theoretical and experimental approaches.

Contribution

It introduces the concept of mesoscopic cross-film cryotrons, demonstrating vortex trapping and oscillatory critical current behavior in a new superconducting device.

Findings

Critical current oscillates with control wire current due to vortex trapping.

Discrete vortex number changes cause critical current oscillations.

Experimental and theoretical results agree on vortex-induced effects.

Abstract

We investigate theoretically and experimentally the transport properties of a plain Al superconducting strip in the presence of a single straight current-carrying wire, oriented perpendicular to the superconducting strip. It is well known that the critical current of the superconducting strip, Ic, in such cryotron--like system can be tuned by changing the current in the control wire, Iw. We demonstrated that the discrete change in the number of the pinned vortices/antivortices inside the narrow and long strip nearby the current-carrying wire results in a peculiar oscillatory dependence of Ic on Iw.