We have investigated the magnetization dynamics in single and trilayer circular permalloy nanodots with a diameter of 120 nm using broadband ferromagnetic resonance spectroscopy. For single-layer nanodots, two well-separated modes near the saturation field, a high-frequency center mode due to excitations at the center of the nanodots and a low-frequency edge mode due to the inhomogeneous effective field near the edges, were observed. Both the center mode and the edge mode are found to be sensitive to the thickness of the nanodots. However, for trilayer nanodots, two center modes arise due to the in-phase and out-of-phase precession of spins in magneto-dynamically coupled layers. Our experimental results are substantiated by micromagnetic simulations, which are in good agreement.

中文翻译：

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单层和三层坡莫合金纳米点的磁化动力学

我们使用宽带铁磁共振光谱研究了直径为 120 nm 的单层和三层圆形坡莫合金纳米点的磁化动力学。对于单层纳米点，在饱和场附近观察到两种分离良好的模式，由于纳米点中心激发产生的高频中心模式和由于边缘附近不均匀有效场产生的低频边缘模式. 发现中心模式和边缘模式都对纳米点的厚度敏感。然而，对于三层纳米点，由于磁动力耦合层中自旋的同相和异相进动，会产生两种中心模式。我们的实验结果得到了微磁模拟的证实，它们非常吻合。