Considerable enhancement of the critical current in a superconducting film by magnetized magnetic strip

TL;DR

This study demonstrates that adding a magnetized strip atop a superconducting film can significantly increase its critical current and induce diode effects, with experimental validation on Nb/Co structures.

Contribution

It introduces a novel method to enhance superconducting critical current using a magnetized strip and explains the underlying magnetic field influence on current distribution.

Findings

Critical current is substantially increased by the magnetic strip.

The diode effect depends on the magnetization direction.

Experimental results confirm the theoretical predictions.

Abstract

We show that a magnetic strip on top of a superconducting strip magnetized in a specified direction may considerably enhance the critical current in the sample. At fixed magnetization of the magnet we observed diode effect - the value of the critical current depends on the direction of the transport current. We explain these effects by a influence of the nonuniform magnetic field induced by the magnet on the current distribution in the superconducting strip. The experiment on a hybrid Nb/Co structure confirmed the predicted variation of the critical current with a changing value of magnetization and direction of the transport current.