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 _Ir = 0.6 nm, 1.2 nm)/CoFeB(13 nm). 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 t _Ir = 0.6 nm, and between 0.09 GHz and 1.4 GHz for t _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.

合成反铁磁体中的磁振子-磁振子耦合将其作为混合磁子系统推进，以探索量子信息技术。为了诱导磁子-磁子耦合，需要打破两个磁化之间的奇偶对称性。在这里，我们通过实验证明了一种通过不对称结构打破奇偶对称性的简便方法。我们成功地在基于 Ir 的合成反铁磁体 CoFeB(10 nm)/Ir( t _Ir = 0.6 nm, 1.2 nm)/CoFeB(13 nm) 中引入了磁振子-磁振子耦合。值得注意的是，我们发现弱单轴各向异性场（~20 Oe）使磁振子-磁振子耦合各向异性。对于t _Ir，由特征反交叉间隙呈现的耦合强度在 0.54 GHz 和 0.90 GHz 之间变化= 0.6 nm，对于t _Ir = 1.2 nm ，介于 0.09 GHz 和 1.4 GHz 之间。我们的结果证明了一种通过不对称结构诱导磁振子-磁振子耦合并通过改变面内磁场方向来调整耦合强度的可行方法。这种高度可调的材料系统中的磁振子-磁振子耦合可以为探索量子力学耦合现象开辟令人兴奋的前景。