Superconducting Triplet Rim Currents in a Spin-Textured Ferromagnetic Disk

Area of Science:

• Condensed Matter Physics
• Superconductivity
• Spintronics

Background:

• The long-range superconducting proximity effect is crucial for understanding Cooper pair interactions.
• Experimental studies on spin-triplet Cooper pairs interacting with magnetic structures are limited.

Purpose of the Study:

• To experimentally investigate the interaction between spin-triplet Cooper pairs and magnetic vortices.
• To develop nanostructured Josephson junctions with controllable spin texture.

Main Methods:

• Fabrication of disk-shaped niobium/cobalt (Nb/Co) bilayer Josephson junctions.
• Utilizing vortex magnetization in cobalt to induce superconductivity in niobium.
• Characterizing the emergence of long-range triplet (LRT) superconductivity.

Main Results:

• LRT superconductivity was induced in the ferromagnet by the interplay of Nb Cooper pairs and Co vortex magnetization.
• Robust LRT correlations were observed in localized (sub-80 nm) channels at the ferromagnet's rim.
• Magnetization texture was identified as an effective spin-orbit coupling mechanism, causing spin accumulation.

Conclusions:

• The study demonstrates a novel mechanism for generating LRT superconductivity in ferromagnets.
• Device spin texture can be manipulated to achieve both 0 and π superconducting channels.
• This work opens new avenues for spintronic devices utilizing superconductivity.