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Phase control in a spin-triplet SQUID.
Joseph A Glick1, Victor Aguilar1, Adel B Gougam1,2
1Michigan State University, East Lansing, MI 48824, USA.
Science Advances
|August 1, 2018
Summary
Researchers demonstrated a controllable phase shift in Josephson junctions with three magnetic layers. This breakthrough in spin-triplet supercurrents could enable memory elements for superconducting computers.
Area of Science:
- Condensed Matter Physics
- Superconductivity
- Spintronics
Background:
- Conventional spin-singlet superconductors with ferromagnetic layers can exhibit spin-triplet supercurrents.
- Experimental evidence for spin-triplet supercurrent propagation over long distances in ferromagnets exists.
- A key theoretical prediction regarding phase shifts in three-magnetic-layer Josephson junctions remains experimentally unverified.
Purpose of the Study:
- To experimentally verify the predicted ground-state phase shift in Josephson junctions with three coplanar magnetic layers.
- To demonstrate phase controllability by manipulating the magnetization of one layer.
- To explore potential applications in superconducting computing.
Main Methods:
- Fabrication of Josephson junctions with three distinct magnetic layers.
- Design allowing 180° magnetization switching of one layer independently.
- Phase-sensitive detection utilizing a superconducting quantum interference device (SQUID).
Main Results:
- Demonstrated a ground-state phase shift of 0 or π in the Josephson junction.
- Phase shift was controllable by altering the relative magnetization orientations.
- Successful phase-sensitive detection confirmed the junction's properties.
Conclusions:
- Experimental verification of the predicted phase shift in three-magnetic-layer Josephson junctions.
- The phase-controllable junction is a viable candidate for memory elements in superconducting computers.
- Advances in spintronic superconducting devices.
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