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Giant oscillatory Gilbert damping in superconductor/ferromagnet/superconductor junctions.
Yunyan Yao1,2, Ranran Cai1,2, Tao Yu3
1International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
Science Advances
|November 26, 2021
Summary
Giant oscillatory Gilbert damping was observed in superconducting niobium/nickel-iron/niobium junctions. This suggests unconventional spin dynamics in ferromagnet/superconductor heterostructures, relevant for quantum computing applications.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Information Science
Background:
- Ferromagnet/superconductor heterostructures exhibit unique physical properties due to the interplay between magnetism and superconductivity.
- Zero- and π-junctions are of significant interest for both fundamental research and technological advancements.
Purpose of the Study:
- To experimentally investigate the behavior of Gilbert damping in superconducting niobium/nickel-iron/niobium junctions.
- To explore the role of zero-energy Andreev bound states in these heterostructures.
Main Methods:
- Fabrication of superconducting niobium/nickel-iron/niobium junctions.
- Experimental measurement of Gilbert damping as a function of nickel-iron layer thickness.
Main Results:
- Observation of giant oscillatory Gilbert damping in the junctions.
- Evidence for unconventional spin pumping and relaxation mechanisms.
- Identification of zero-energy Andreev bound states in both zero- and π-junctions.
Conclusions:
- The findings highlight exotic physical properties in ferromagnet/superconductor heterostructures.
- Potential applications for ferromagnet π-junctions in quantum computing, specifically in half-quantum flux qubits, are suggested.
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