物理学进展

物理学进展 ›› 2023, Vol. 43 ›› Issue (5): 142-150.doi: 10.13725/j.cnki.pip.2023.05.002

所属专题： 2023年, 第43卷

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Cr2O3 中反铁磁自旋波的低频拉曼光谱研究

  

  1. 南京大学物理学院，固体微结构物理国家重点实验室，南京 210093
  • 出版日期:2023-10-20 发布日期:2023-10-23

Low-Frequency Raman Detection of Antiferromagnetic Spin Waves in Cr2O3

  1. National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
  • Online:2023-10-20 Published:2023-10-23
  • Supported by:
     National Key Research, Development Program of China (2020YFA0309200) and National Natural Science Foundation of China (52025012)

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摘要： 反铁磁自旋波在高速和低能耗信息处理方面具有很大潜力。然而，在反铁磁体系中激发和 检测太赫兹自旋波是具有挑战性的。在本工作中，我们验证了低频拉曼光谱可作为探测反铁磁体 系中自旋波的有力工具。我们通过拉曼光谱系统研究了典型的单轴反铁磁体 Cr2O3 中的反铁磁自 旋波，我们的测量范围低至 2.3 cm−1（69 GHz）。我们分析了自旋波的塞曼劈裂和自旋翻转相变。 我们进一步通过偏振拉曼的方式确定了自旋波能支的角动量符号。我们还得到了 Cr2O3 的各向异 性能，g 因子和自旋翻转场随温度和磁场变化的函数关系。自旋波重整化理论解释了所有实验观 测结果。

关键词: 反铁磁性, 自旋波, 低频拉曼光谱, 自旋翻转

Abstract:

The antiferromagnetic (AFM) spin waves are promising for being utilized in highspeed and energy-efficient information processing. However, the excitation and detection of terahertz spin waves in AFM systems is challenging. Here, we demonstrate low-frequency Raman spectroscopy as a powerful tool for spin-wave detection in AFM systems. We present a systematic study of AFM magnons in Cr2O3, a prototypical uniaxial antiferromagnet, via Raman measurements down to 2.3 cm−1 (69 GHz). We resolved the magnon Zeeman splitting and the spin-flop transition. We further determined the sign of angular momentum of the magnon branches via polarization-resolved Raman processes. We also obtained the anisotropy energy, the g-factor, and the spin-flop field of Cr2O3 as a function of temperatures and magnetic fields. A spin-wave renormalization theory accounts for all experimental observations. 

Key words: antiferromagnetism, spin wave, low-frequency Raman spectroscopy, spin-flop

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