Altermagnetic order, characterized by the N\'{e}el vector, breaks time-reversal symmetry (TRS) even in the nonrelativistic limit. Although spin-polarized and anomalous transport phenomena emerge with this order, they are mutually compensated by TRS-connected antiphase domains with opposite N\'{e}el vectors. Here we employ polarized neutron diffraction to directly probe the altermagnetic order in MnTe. Pronounced nuclear-magnetic interference terms were observed, providing direct evidence of a net N\'{e}el vector in the bulk crystal. Moreover, a weak ferromagnetic moment (WFM), originating from relativistic spin-orbit coupling, was found to be coupled with the altermagnetic order. Both the altermagnetic order and the WFM can be switched by milli-Tesla-scale magnetic field cooling.
@article{arxiv.2605.21616,
title = {Observation of Altermagnetic Order Switching in Bulk MnTe by Polarized Neutron Diffraction},
author = {Zheyuan Liu and Shinichiro Asai and Shingo Takahashi and Hiraku Saito and Taro Nakajima and Takatsugu Masuda},
journal= {arXiv preprint arXiv:2605.21616},
year = {2026}
}
Comments
8 pages, 4 figures. Accepted for publication in Phys. Rev. Lett