近日，北京航空航天大学于海明团队研究了倾斜反铁磁体中磁振子干涉对自旋电流的控制。2025年4月23日出版的《自然—物理学》杂志发表了这项成果。
控制自旋电流是自旋电子学及其应用的核心。在铁磁体中，一旦确定了电流方向，自旋电流的符号就固定了。然而，反铁磁体中的自旋电流可以具有相反的极化，但这需要巨大的磁场来解除两种模式之间的简并。因此，控制具有相反极化的自旋电流仍然是一个挑战。
研究组演示了倾斜反铁磁体（即最近被归类为交替磁体的赤铁矿）中磁振子干涉在室温下对自旋电流的控制。布里渊光散射的磁光特性表明，拍频图案的空间周期性可以通过微波频率进行调节。研究组进一步观察到，随着频率的调谐，反向自旋霍尔电压的符号会发生变化，这表明纯自旋电流的极化是频率控制的。该工作强调了使用反铁磁振子干涉来控制自旋电流，这大大扩展了相干反铁磁自旋电子学新兴领域的视野。
附：英文原文
Title: Control of spin currents by magnon interference in a canted antiferromagnet
Author: Sheng, Lutong, Duvakina, Anna, Wang, Hanchen, Yamamoto, Kei, Yuan, Rundong, Wang, Jinlong, Chen, Peng, He, Wenqing, Yu, Kanglin, Zhang, Yuelin, Chen, Jilei, Hu, Junfeng, Song, Wenjie, Liu, Song, Han, Xiufeng, Yu, Dapeng, Ansermet, Jean-Philippe, Maekawa, Sadamichi, Grundler, Dirk, Yu, Haiming
Issue&Volume: 2025-04-23
Abstract: Controlling the spin current lies at the heart of spintronics and its applications. In ferromagnets, the sign of spin currents is fixed once the current direction is determined. However, spin currents in antiferromagnets can possess opposite polarizations, but this requires enormous magnetic fields to lift the degeneracy between the two modes. Therefore, controlling spin currents with opposite polarization is still a challenge. Here we demonstrate the control of spin currents at room temperature by magnon interference in a canted antiferromagnet, namely, haematite that has recently been classified as an altermagnet. Magneto-optical characterization by Brillouin light scattering reveals that the spatial periodicity of the beating patterns is tunable via the microwave frequency. We further observe that the inverse spin Hall voltage changes sign as the frequency is tuned, evincing a frequency-controlled switching of polarization of pure spin currents. Our work highlights the use of antiferromagnetic magnon interference to control spin currents, which substantially extends the horizon for the emerging field of coherent antiferromagnetic spintronics.
DOI: 10.1038/s41567-025-02819-7
Source: https://www.nature.com/articles/s41567-025-02819-7