Seminars

Title:  Observation of gapless magnons in antiferromagnets
 
Abstract: Antiferromagnetic magnons possess high speed and are immune to external disturbance,making them promising for future magnonic circuits [1]. In this talk, I will present the experimental observation of gapless magnons in an easy-axis antiferromagnet α-Fe₂O₃ (also known as hematite) at low temperatures (~6 K). These antiferromagnetic magnons are detected at nearly zero frequency byall-electrical spin-wave spectroscopy, substantially below the antiferromagnetic resonance gap (~160 GHz). The gapless magnons are found to propagate along and within the channel of antiferromagnetic domain walls as revealed by our theoretical model and simulations[2]. At the end, I will briefly discuss our recent results on themagnon bound states trapped in an interfacial exchange-induced potential well, observed in a ferromagnet-antiferromagnet hybrid nanostructure [3].

[1]J. Han, R. Cheng, L. Liu, H. Ohno and S. Fukami, Coherent antiferromagnetic spintronics, Nat. Mater. 22, 684-695 (2023).

[2]J. Chen*, Z. Jin, R. Yuan, H. Wang, H. Jia, W. Wei, L. Sheng, J.Wang, Y. Zhang, S. Liu, D. Yu, J.-Ph. Ansermet, P. Yan* and H. Yu*, Phys. Rev. Lett. 134,056701 (2025).

[3]J.Wang, B. Dey, M. Grammer, H. Wang, R. Yuan, H. Song, T. Yang, J.Chen, S. Liu, D. Yu, J. Xiao, A. Kamra*, M. Althammer* and H. Yu*(under preparation)