Cr2O3中反铁磁自旋波的低频拉曼光谱研究

Low-Frequency Raman Detection of Antiferromagnetic Spin Wavesin Cr2O3

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。

The antiferromagnetic(AFM)spin waves are promising for being utilized in high-speed 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.