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Chinese Academy of Sciences

Asynchronous Ferromagnetic Resonance Observed in Antiferromagnetically Coupled Sublattices

Strategic Insights

— 1 min read

Researchers at the Chinese Academy of Sciences have made a significant discovery in the field of applied physics, observing asynchrony among sublattices in typical CoGd ferrimagnets. This finding has significant implications for the development of magnonic and spintronic devices, which rely on the properties of antiferromagnetically coupled sublattices. The researchers used magnetic resonance to demonstrate that the asynchrony occurs when the resonance frequency exceeds a critical value, corresponding to the delay time between the two sublattices under microwave excitations.

Key Takeaways:

  • The researchers observed asynchrony among sublattices in typical CoGd ferrimagnets, which fail to remain synchronized during high-speed precession.
  • The asynchrony was observed to occur when the resonance frequency exceeds a critical value corresponding to the delay time between the two sublattices under microwave excitations.
  • The delay time (tau(d)) was determined to be about 60 ps in CoGd, which varies slightly with temperature and composition, but decreases sharply near magnetization and angular momentum compensation.
  • The results demonstrate the speed limit of device performance relying on the antiferromagnetically coupled sublattices as a matter of fundamental principle.
  • The antiferromagnetic attributes during high-speed operations cannot be described as statically coupled sublattices.
  • The research has been peer-reviewed and published in the Applied Physics Letters.
  • The study was funded by the Beijing Natural Science Foundation, Ministry of Science and Technology, China, National Natural Science Foundation of China (NSFC), Chinese Academy of Sciences, and Fundamental Research Funds for the Central Universities.

Statistics:

  • The delay time (tau(d)) was determined to be about 60 ps in CoGd.
  • The asynchrony was observed to occur when the resonance frequency exceeded a critical value of about 23.4 GHz.
  • The study was funded by the Beijing Natural Science Foundation, Ministry of Science and Technology, China, National Natural Science Foundation of China (NSFC), Chinese Academy of Sciences, and Fundamental Research Funds for the Central Universities.

Sources:

  • NewsRx. Recent Research from Chinese Academy of Sciences Highlight Findings in Applied Physics (Observation of Asynchronous Ferromagnetic Resonance In Antiferromagnetically Coupled Sublattices). Journal of Physics Research. October 21, 2025; p 446.
  • Bi, C., et al. Observation of Asynchronous Ferromagnetic Resonance In Antiferromagnetically Coupled Sublattices. Applied Physics Letters, 2025;127(12).
  • Aip Publishing. Applied Physics Letters. 1305 Walt Whitman Rd, Ste 300, Melville, NY 11747-4501, USA. (www.aip.org/; apl.aip.org/)
  • Chinese Academy of Sciences. Institute for Microelectronics, Lab Microelect Devices & Integrated Technol, Beijing 100029, People's Republic of China.

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