Mesoscopic field and current compensator based on a hybrid superconductor-ferromagnet structure

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• Superconductivity (SC) is a quantum mechanical phenomenon where a material exhibits zero electrical resistance.
• Ferromagnetic (FM) materials possess spontaneous magnetization, influencing electronic properties.

Purpose of the Study:

• To investigate the enhancement of superconductivity in a hybrid structure combining a submicron superconducting sample with an in-plane ferromagnet.
• To understand the effects of ferromagnetism on the critical magnetic field and current-carrying capacity of superconductors.

Main Methods:

• Fabrication of a hybrid SC-FM structure at the submicron scale.
• Experimental characterization of superconducting properties under applied magnetic fields and currents.

Main Results:

• Demonstrated general enhancement of superconductivity in the hybrid SC-FM structure.
• Observed increased resistance to higher applied magnetic fields due to magnetic field screening by the FM.
• Identified induced opposing currents in the SC plane by the FM, leading to compensation effects.
• Showcased persistence of superconductivity up to higher applied currents.

Conclusions:

• Hybrid SC-FM structures offer a general route to enhance superconducting properties.
• The interplay between ferromagnetism and superconductivity can be leveraged to improve device performance in terms of magnetic field and current tolerance.
• SC-"resistive"-normal state transitions occur via vortex-antivortex and phase-slip phenomena with increasing current.