Anisotropic Magnon-Magnon Coupling in Synthetic Antiferromagnets

• 作 者: 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 Jie Lu
• 机 构: State Key Laboratory of Magnetism and Beijing National Laboratory for Condensed Matter Physics,Insti
• 出 处: 中国物理快报（英文版）
• 发表日期: 2021年5期

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(10nm)/Ir(tIr =0.6nm,1.2nm)/CoFeB(13nm).Remarkably,we find that the weakly uniaxial anisotropy field (～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 tIr =0.6 nm,and between 0.09 GHz and 1.4 GHz for tIr =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.