Toward the Absolute Spin-Valve Effect in Superconducting Tunnel Junctions.

Area of Science:

• Condensed Matter Physics
• Spintronics
• Superconductivity

Background:

• Spin-split superconductors exhibit ideal ferromagnetic spin-injector properties.
• Theoretical models predict tunable spin-valves from two such superconductors.
• Previous research lacked experimental realization of switchable superconducting spin-valves.

Purpose of the Study:

• To experimentally demonstrate the first switchable superconducting spin-valve.
• To investigate the potential of EuS/Al bilayers for spintronic applications.
• To explore the feasibility of superconducting spin-valves in cryogenic devices.

Main Methods:

• Fabrication of a tunneling junction using two EuS/Al bilayers.
• Coupling of bilayers through an aluminum oxide tunnel barrier.
• Measurement of resistance changes under varying magnetic configurations.

Main Results:

• Achieved a switchable superconducting spin-valve.
• Observed a relative resistance change up to 900% between parallel and antiparallel configurations.
• Demonstrated highly spin-polarized current through the junction.

Conclusions:

• The developed device functions as an ideal absolute spin-valve.
• This technology is crucial for thermoelectric radiation detectors and cryogenic memory cells.
• The findings advance the field of superconducting spintronics and superconductor-based computing.