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Published on: June 7, 2018
Observation of Altermagnetic Order Switching in Bulk MnTe by Polarized Neutron Diffraction.
Zheyuan Liu1, Shinichiro Asai1, Shingo Takahashi1
1the University of Tokyo, Institute for Solid State Physics, Kashiwa 277-8581, Japan.
Physical Review Letters
|July 10, 2026
Summary
Researchers directly observed altermagnetic order in MnTe using polarized neutron diffraction. This revealed a net Néel vector and coupled weak ferromagnetic moment, switchable by magnetic field cooling.
Area of Science:
- Solid State Physics
- Materials Science
- Magnetism
Background:
- Altermagnetic order breaks time-reversal symmetry (TRS) but its effects are often compensated.
- Understanding altermagnetism in materials like MnTe is crucial for novel electronic applications.
Purpose of the Study:
- To directly probe and confirm the presence of altermagnetic order in MnTe.
- To investigate the coupling between altermagnetic order and weak ferromagnetism.
- To determine the switchability of these magnetic orders.
Main Methods:
- Polarized neutron diffraction was employed to investigate the magnetic structure of MnTe.
- Nuclear-magnetic interference terms were analyzed to detect the Néel vector.
- Magnetic field cooling protocols were used to assess order switching.
Main Results:
- Direct evidence of a net Néel vector in bulk MnTe was obtained via polarized neutron diffraction.
- A weak ferromagnetic moment (WFM), linked to spin-orbit coupling, was observed and found to be coupled with the altermagnetic order.
- Both altermagnetic order and WFM were demonstrated to be switchable using milli-Tesla scale magnetic field cooling.
Conclusions:
- Polarized neutron diffraction is a powerful tool for directly observing altermagnetic order.
- MnTe exhibits coupled altermagnetic and weak ferromagnetic orders.
- The observed magnetic orders are controllable via magnetic field cooling, suggesting potential for spintronic devices.
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