It is desirable to experimentally demonstrate an extremely high resonant frequency, assisted by strain-spin coupling, in technologically important perpendicular magnetic materials for device applications. Here, we directly observe the coupling of magnons and phonons in both time and frequency domains upon femtosecond laser excitation. This strain-spin coupling leads to a magnetoacoustic resonance in perpendicular magnetic [Co/Pd]_n multilayers, reaching frequencies in the extremely high frequency (EHF) band, e.g., 60 GHz. We propose a theoretical model to explain the physical mechanism underlying the strain-spin interaction. Our model explains the amplitude increase of the magnetoacoustic resonance state with time and quantitatively predicts the composition of the combined strain-spin state near the resonance. We also detail its precise dependence on the magnetostriction. The results of this work offer a potential pathway to manipulating both the magnitude and timing of EHF and strongly coupled magnon-phonon excitations.

期望通过实验证明在用于设备应用的技术上重要的垂直磁性材料中，在应变自旋耦合的辅助下具有极高的谐振频率。在这里，我们直接观察到飞秒激光激发时时域和频域中的磁振子和声子的耦合。这种应变自旋耦合导致垂直磁[Co / Pd] _n中的磁声共振多层，达到极高频（EHF）频段的频率，例如60 GHz。我们提出了一个理论模型来解释应变-自旋相互作用的物理机制。我们的模型解释了磁声共振状态随时间的振幅增加，并定量预测了共振附近组合的应变自旋状态的组成。我们还详细介绍了其对磁致伸缩的精确依赖性。这项工作的结果为操纵EHF的幅度和时间以及强耦合的磁振子-声子激发提供了一条潜在的途径。