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Nonlocal Coupling between Antiferromagnets and Ferromagnets in Cavities
Øyvind Johansen1, Arne Brataas1
1Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
Physical Review Letters
|September 8, 2018
Summary
Microwaves can entangle magnetic excitations called magnons in both ferromagnets and antiferromagnets. This study reveals a strong, comparable coupling between these distinct magnetic systems, linking cavity spintronics.
Area of Science:
- Cavity spintronics
- Quantum magnetism
- Magnon-photon interactions
Background:
- Microwaves interact with magnetic moments in both ferromagnetic and antiferromagnetic materials.
- Magnons, the quantum excitations of magnetic moments, differ significantly between ferromagnets and antiferromagnets.
Purpose of the Study:
- To investigate the entanglement of magnons from ferromagnets and antiferromagnets via a shared microwave cavity mode.
- To derive analytical expressions for magnon coupling strengths.
- To compare the coupling between different magnetic systems.
Main Methods:
- Theoretical derivation of coupling strengths.
- Analysis of magnon-photon coupling in a cavity.
- Consideration of magnetic moment equilibrium configurations and spin interactions.
Main Results:
- Ferromagnetic and antiferromagnetic magnons can become entangled through strong coupling to a common microwave cavity mode.
- Analytical expressions for coupling strengths were derived.
- The coupling between antiferromagnets and ferromagnets is found to be comparable to that between two ferromagnets.
Conclusions:
- A robust link exists between cavity spintronics involving ferromagnets and antiferromagnets.
- The findings pave the way for novel hybrid magnetic systems utilizing both types of magnetic order.
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