Feggeler Thomas, Meckenstock Ralf, Spoddig Detlef, Schöppner Christian, Zingsem Benjamin, Schaffers Taddäus, Ohldag Hendrik, Wende Heiko, Farle Michael, Ney Andreas, Ollefs Katharina
Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47048, Duisburg, Germany.
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
Sci Rep. 2022 Nov 4;12(1):18724. doi: 10.1038/s41598-022-23273-y.
We present the element-specific and time resolved visualization of uniform ferromagnetic resonance excitations of a Permalloy (Py) disk-Cobalt (Co) stripe bilayer microstructure. The transverse high frequency component of the resonantly excited magnetization is sampled in the ps regime by a combination of ferromagnetic resonance (FMR) and scanning transmission X-ray microscopy (STXM-FMR) recording snapshots of the local magnetization precession of Py and Co with nanometer spatial resolution. The approach allows us to individually image the resonant dynamic response of each element, and we find that angular momentum is transferred from the Py disk to the Co stripe and vice versa at their respective resonances. The integral (cavity) FMR spectrum of our sample shows an unexpected additional third resonance. This resonance is observed in the STXM-FMR experiments as well. Our microscopic findings suggest that it is governed by magnetic exchange between Py and Co, showing for the Co stripe a difference in relative phase of the magnetization due to stray field influence.
我们展示了坡莫合金（Py）圆盘 - 钴（Co）条纹双层微观结构中均匀铁磁共振激发的元素特异性和时间分辨可视化。通过铁磁共振（FMR）和扫描透射X射线显微镜（STXM - FMR）的组合，在皮秒（ps）时间尺度上对共振激发磁化的横向高频分量进行采样，以纳米空间分辨率记录Py和Co的局部磁化进动的快照。该方法使我们能够分别成像每个元素的共振动态响应，并且我们发现角动量在Py圆盘和Co条纹各自的共振频率下在它们之间相互传递。我们样品的积分（腔）FMR光谱显示出一个意外的额外第三共振。这种共振在STXM - FMR实验中也被观察到。我们的微观研究结果表明，它受Py和Co之间的磁交换支配，显示出由于杂散场影响，Co条纹的磁化相对相位存在差异。
