Large ultrafast-modulated Voigt effect in noncollinear antiferromagnet Mn3Sn

H C Zhao; H Xia; S Hu; Y Y Lv; Z R Zhao; J He; E Liang; G Ni; L Y Chen; X P Qiu; S M Zhou; H B Zhao

doi:10.1038/s41467-021-25654-9

Large ultrafast-modulated Voigt effect in noncollinear antiferromagnet Mn₃Sn

Nat Commun. 2021 Sep 6;12(1):5266. doi: 10.1038/s41467-021-25654-9.

Authors

H C Zhao¹, H Xia^{1

2}, S Hu³, Y Y Lv³, Z R Zhao¹, J He¹, E Liang¹, G Ni⁴, L Y Chen¹, X P Qiu⁵, S M Zhou⁶, H B Zhao^{7

8}

Affiliations

¹ Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), and Shanghai Ultra-precision Optical Manufacturing Engineering Research Center, Department of Optical Science and Engineering, Fudan University, Shanghai, China.
² Department of Physics, Fudan University, Shanghai, China.
³ Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology and Pohl Institute of Solid State Physics and School of Physics Science and Engineering, Tongji University, Shanghai, China.
⁴ Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), and Shanghai Ultra-precision Optical Manufacturing Engineering Research Center, Department of Optical Science and Engineering, Fudan University, Shanghai, China. gni@fudan.edu.cn.
⁵ Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology and Pohl Institute of Solid State Physics and School of Physics Science and Engineering, Tongji University, Shanghai, China. xpqiu@tongji.edu.cn.
⁶ Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology and Pohl Institute of Solid State Physics and School of Physics Science and Engineering, Tongji University, Shanghai, China. shiming@tongji.edu.cn.
⁷ Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), and Shanghai Ultra-precision Optical Manufacturing Engineering Research Center, Department of Optical Science and Engineering, Fudan University, Shanghai, China. hbzhao@fudan.edu.cn.
⁸ Shanghai Frontier Base of Intelligent Optoelectronics and Perception, Institute of Optoelectronics, Fudan University, Shanghai, China. hbzhao@fudan.edu.cn.

Abstract

The time-resolved magneto-optical (MO) Voigt effect can be utilized to study the Néel order dynamics in antiferromagnetic (AFM) materials, but it has been limited for collinear AFM spin configuration. Here, we have demonstrated that in Mn₃Sn with an inverse triangular spin structure, the quench of AFM order by ultrafast laser pulses can result in a large Voigt effect modulation. The modulated Voigt angle is significantly larger than the polarization rotation due to the crystal-structure related linear dichroism effect and the modulated MO Kerr angle arising from the ferroic ordering of cluster magnetic octupole. The AFM order quench time shows negligible change with increasing temperature approaching the Néel temperature (T_N), in markedly contrast with the pronounced slowing-down demagnetization typically observed in conventional magnetic materials. This atypical behavior can be explained by the influence of weakened Dzyaloshinskii-Moriya interaction rather than the smaller exchange splitting on the diminished AFM order near T_N. The temperature-insensitive ultrafast spin manipulation can pave the way for high-speed spintronic devices either working at a wide range of temperature or demanding spin switching near T_N.

Grants and funding

11774064/National Natural Science Foundation of China (National Science Foundation of China)