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Zero phase difference supercurrent in ferromagnetic Josephson junctions
I Margaris1, V Paltoglou, N Flytzanis
1Department of Physics, University of Crete, Heraklion, Greece.
Summary
We found that non-coplanar magnetizations in ferromagnetic Josephson junctions can create a zero phase difference supercurrent. This occurs due to broken time-reversal symmetry, a key finding for spintronic devices.
Area of Science:
- Condensed Matter Physics
- Spintronics
- Superconductivity
Background:
- Ferromagnetic Josephson junctions are crucial for spintronic devices.
- Spin-active interfaces and non-coplanar magnetization can influence superconducting properties.
- Understanding the conditions for supercurrent flow is essential for device applications.
Purpose of the Study:
- To investigate the emergence of zero phase difference supercurrent in ballistic ferromagnetic Josephson junctions.
- To analyze the role of non-coplanar magnetization and time-reversal symmetry.
- To derive a generalized formula for equilibrium supercurrent.
Main Methods:
- Analytical analysis of the junction's Hamiltonian.
- Numerical simulations of the system's behavior.
- Derivation of a new formula for equilibrium supercurrent.
Main Results:
- A zero phase difference supercurrent appears when magnetizations are non-coplanar.
- The presence of a single magnetization vector breaks time-reversal symmetry, enabling this supercurrent.
- Symmetry restoration (and suppression of the zero phase difference supercurrent) occurs with coplanar magnetizations.
Conclusions:
- Non-coplanar magnetizations in ferromagnetic Josephson junctions are a key factor for generating zero phase difference supercurrent.
- Time-reversal symmetry breaking is crucial for this phenomenon, unless specific symmetries are present.
- The derived formula offers a generalized understanding of equilibrium supercurrent in such systems.
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