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Updated: Jun 24, 2026
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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Altermagnetic and Dipolar Splitting of Magnons in FeF_{2}
J Sears1, V O Garlea2, D Lederman3,4
1Brookhaven National Laboratory, Condensed Matter Physics and Materials Science Division, Upton, New York 11973-5000, USA.
Physical Review Letters
|June 22, 2026
Summary
In iron difluoride (FeF2), dipolar interactions, not altermagnetic exchange, primarily cause magnon splitting. Altermagnetic chiral splitting is observed but is weak, showing dipolar effects on magnon chirality.
Area of Science:
- Condensed Matter Physics
- Quantum Materials
- Magnetism
Background:
- Iron difluoride (FeF2) is an antiferromagnet with rutile structure.
- It was recently proposed to exhibit altermagnetic properties, allowing for spin-split bands and chiral magnons.
Purpose of the Study:
- To investigate the origin of magnon splitting in FeF2.
- To quantify the contributions of dipolar interactions and altermagnetic exchange to magnon chirality.
Main Methods:
- Very-high-resolution inelastic neutron scattering on a single crystal of FeF2.
- Polarized neutron scattering measurements.
Main Results:
- The dominant source of magnon splitting in FeF2 is the long-range dipolar interaction, not altermagnetic exchange.
- Altermagnetic chiral splitting was observed as broadening at specific momenta, estimated at ~35 μeV.
- Dipolar interactions lead to mixing of chiral magnon modes, resulting in predominantly linearly polarized modes.
Conclusions:
- Dipolar interactions significantly influence magnon chirality in FeF2.
- The effect of altermagnetic interactions on magnon chirality is weak compared to dipolar effects.
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