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Published on: July 14, 2021
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Ultrafast Control of Néel Vector in Collinear Antiferromagnet MnPt
Sambhu Jana1,2, Sobhan Subhra Mishra1,2, James Lourembam3
1Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
|November 10, 2025
Summary
This study reveals ultrafast antiferromagnetic (AFM) magnetization dynamics in exchange-bias-coupled spintronic terahertz emitters (EBC-STEs). This breakthrough transforms AFM from a passive component into a sensitive probe of interfacial magnetism.
Area of Science:
- Spintronics
- Terahertz (THz) photonics
- Antiferromagnetic (AFM) materials
Background:
- Exchange-bias-coupled spintronic terahertz emitters (EBC-STEs) conventionally use antiferromagnets (AFMs) as passive pinning layers.
- Ultrafast dynamics of AFMs were considered undetectable due to their zero net magnetic moment, limiting their role in terahertz (THz) emission.
Purpose of the Study:
- To demonstrate a novel method for probing and controlling ultrafast magnetization dynamics in AFMs within EBC-STEs.
- To investigate the stability of EBC-STEs compared to conventional spintronic terahertz emitters (STEs).
Main Methods:
- Utilized laser-induced optical torque to drive Néel vector dynamics in collinear AFM MnPt.
- Isolated and detected distinct THz emission from the canted magnetic moment in Pt/MnPt bilayers to probe AFM dynamics.
- Compared the stability of EBC-STEs and conventional STEs under optical excitation.
Main Results:
- Successfully demonstrated and detected ultrafast AFM magnetization dynamics driven by optical torque.
- Confirmed that the THz emission from the canted magnetic moment originates from the AFM subsystem.
- Provided direct evidence of AFM dynamics influencing THz emission in EBC-STEs.
Conclusions:
- Antiferromagnetic (AFM) magnetization dynamics can be directly probed and controlled in EBC-STEs.
- EBC-STEs can function as sensitive probes of interfacial ultrafast magnetism.
- This research unlocks the potential of antiferromagnetic THz spintronics.
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