Anisotropic Magnon–Magnon Coupling in Synthetic Antiferromagnets
Wei He1*, Z. K. Xie1, Rui Sun1, Meng Yang1, Yang Li1, Xiao-Tian Zhao2*, Wei Liu2, Z. D. Zhang2, Jian-Wang Cai1, Zhao-Hua Cheng1, and Jie Lu3*
1State Key Laboratory of Magnetism and Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China 2Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China 3College of Physics and Hebei Advanced Thin Films Laboratory, Hebei Normal University, Shijiazhuang 050024, China
Abstract：Magnon–magnon coupling in synthetic antiferromagnets advances it as hybrid magnonic systems to explore the quantum information technologies. To induce magnon–magnon coupling, the parity symmetry between two magnetization needs to be broken. Here we experimentally demonstrate a convenient method to break the parity symmetry by the asymmetric structure. We successfully introduce a magnon–magnon coupling in Ir-based synthetic antiferromagnets CoFeB(10 nm)/Ir($t_{_{\scriptstyle \rm Ir}}=0.6$ nm, 1.2 nm)/CoFeB(13 nm). Remarkably, we find that the weakly uniaxial anisotropy field ($\sim $20 Oe) makes the magnon–magnon coupling anisotropic. The coupling strength presented by a characteristic anticrossing gap varies in the range between 0.54 GHz and 0.90 GHz for $t_{_{\scriptstyle \rm Ir}} =0.6$ nm, and between 0.09 GHz and 1.4 GHz for $t_{_{\scriptstyle \rm Ir}} = 1.2$ nm. Our results demonstrate a feasible way to induce magnon–magnon coupling by an asymmetric structure and tune the coupling strength by varying the direction of in-plane magnetic field. The magnon–magnon coupling in this highly tunable material system could open exciting perspectives for exploring quantum-mechanical coupling phenomena.
收稿日期: 2021-03-15
出版日期: 2021-05-02
引用本文:
. [J]. 中国物理快报, 2021, 38(5): 57502-.
Wei He, Z. K. Xie, Rui Sun, Meng Yang, Yang Li, Xiao-Tian Zhao, Wei Liu, Z. D. Zhang, Jian-Wang Cai, Zhao-Hua Cheng, and Jie Lu. Anisotropic Magnon–Magnon Coupling in Synthetic Antiferromagnets. Chin. Phys. Lett., 2021, 38(5): 57502-.
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