Tunable Field Induced Superconductivity

TL;DR

This study demonstrates a controllable and erasable field-induced superconductivity in a thin Al film influenced by magnetic dots, with magnetic states fine-tuned to modulate vortex behavior without resistance discontinuities.

Contribution

We introduce a method to continuously tune the magnetic state of dots affecting superconductivity, enabling controllable and erasable field-induced superconductivity.

Findings

Magnetic state of dots can be precisely controlled.

Superconducting resistance remains continuous despite vortex changes.

Superconducting phase boundary can be tuned by magnetic states.

Abstract

We investigate the transport properties of a thin superconducting Al layer covering a square array of magnetic dots with out-of-plane magnetization. A thorough characterization of the magnetic properties of the dots allowed us to fine-tune their magnetic state at will, hereby changing the influence of the dots on the superconductor in a continuous way. We show that even though the number of vortex-antivortex pairs discretely increases with increasing the magnetization of the dots, no corresponding discontinuity is observed in the resistance of the sample. The evolution of the superconducting phase boundary as the magnetic state of the dots is swept permits one to devise a fully controllable and erasable field induced superconductor.