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Optimization of spin-triplet supercurrent in ferromagnetic Josephson junctions
Carolin Klose1, Trupti S Khaire, Yixing Wang
1Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-2320, USA.
Physical Review Letters
|May 1, 2012
Summary
We observed enhanced spin-triplet supercurrents in Josephson junctions by inducing a spin-flop transition in synthetic antiferromagnets using an in-plane field. This transition significantly boosts supercurrents, paving the way for controlling spintronic devices.
Area of Science:
- Condensed matter physics
- Spintronics
- Superconductivity
Background:
- Long-range spin-triplet supercurrents are observed in Josephson junctions with ferromagnetic materials.
- These supercurrents arise from noncollinear magnetizations in multilayered structures.
Purpose of the Study:
- To investigate the enhancement of spin-triplet supercurrents in ferromagnetic Josephson junctions.
- To explore the role of magnetic field-induced transitions in modulating supercurrents.
Main Methods:
- Fabrication of Josephson junctions with a central Co/Ru/Co synthetic antiferromagnet and outer ferromagnetic layers.
- Application of a large in-plane magnetic field to induce a spin-flop transition.
- Characterization using scanning electron microscopy with polarization analysis (SEMPA) and spin-polarized neutron reflectometry (SPNR).
Main Results:
- Spin-triplet supercurrents were enhanced up to 20 times under an in-plane magnetic field.
- The enhancement is attributed to a spin-flop transition in the synthetic antiferromagnet, aligning magnetizations perpendicularly.
- Experimental evidence for the spin-flop transition was confirmed by SEMPA and SPNR.
Conclusions:
- A large in-plane magnetic field can significantly enhance spin-triplet supercurrents in ferromagnetic Josephson junctions.
- The spin-flop transition in synthetic antiferromagnets is a key mechanism for this enhancement.
- These findings represent a crucial advancement in the experimental control of spin-triplet supercurrents for spintronic applications.
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