Cheng Yang, Huang Hanshen, Tang Junyu, Lanier Joseph, Lazareno Katelyn, Chang Hao-Kai, Chui Shang-Jui, Yang Chao-Yao, Yang Fengyuan, Cheng Ran, Wang Kang L
Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA.
Department of Physics and Astronomy, University of California, Riverside, CA, 92507, USA.
Adv Mater. 2025 Mar;37(10):e2417240. doi: 10.1002/adma.202417240. Epub 2025 Jan 26.
In the burgeoning field of spintronics, antiferromagnetic materials (AFMs) are attracting significant attention for their potential to enable ultra-fast, energy-efficient devices. Thin films of AFMs are particularly promising for practical applications due to their compatibility with spin-orbit torque (SOT) mechanisms. However, studying these thin films presents challenges, primarily due to the weak signals they produce and the rapid dynamics driven by SOT, that are too fast for conventional electric transport or microwave techniques to capture. The time-resolved magneto-optical Kerr effect (TR-MOKE) has been a successful tool for probing antiferromagnetic dynamics in bulk materials, thanks to its sub-picosecond (sub-ps) time resolution. Yet, its application to nanometer-scale thin films has been limited by the difficulty of detecting weak signals in such small volumes. In this study, the first successful observation of antiferromagnetic dynamics are presented in nanometer-thick orthoferrite films using the pump-probe technique to detect TR-MOKE signal. This paper report an exceptionally low damping constant of 1.5 × 10 and confirms the AFM magnonic nature of these dynamics through angular-dependent measurements. Furthermore, it is observed that electrical currents can potentially modulate these dynamics via SOT. The findings lay the groundwork for developing tunable, energy-efficient spintronic devices, paving the way for advancements in next-generation spintronic applications.
在蓬勃发展的自旋电子学领域，反铁磁材料因其具有实现超快速、节能器件的潜力而备受关注。反铁磁材料薄膜由于与自旋轨道矩（SOT）机制具有兼容性，在实际应用中尤其具有前景。然而，研究这些薄膜存在挑战，主要是因为它们产生的信号较弱，以及由SOT驱动的快速动力学过程，其速度太快，传统的电输运或微波技术无法捕捉。时间分辨磁光克尔效应（TR-MOKE）凭借其亚皮秒（sub-ps）的时间分辨率，已成为探测块状材料中反铁磁动力学的成功工具。然而，由于在如此小的体积中检测微弱信号存在困难，其在纳米尺度薄膜中的应用受到了限制。在本研究中，首次成功地利用泵浦-探测技术检测TR-MOKE信号，在纳米厚的正铁氧体薄膜中观测到了反铁磁动力学过程。本文报道了一个异常低的阻尼常数1.5×10，并通过角度相关测量证实了这些动力学过程的反铁磁磁振子性质。此外，还观察到电流可以通过SOT潜在地调制这些动力学过程。这些发现为开发可调谐、节能的自旋电子器件奠定了基础，为下一代自旋电子应用的发展铺平了道路。
