Observation of incoherent picosecond magnetisation dynamics in micron sized Ni81Fe19 elements by time resolved scanning Kerr effect microscopy
Observation of incoherent picosecond magnetisation dynamics in micron sized Ni81Fe19 elements by time resolved scanning Kerr effect microscopy
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通过时间分辨扫描克尔效应显微镜观察微米级 Ni81Fe19 元素中非相干皮秒磁化动力学
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发表时间：
2003
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通讯作者：
M. Rahman
中科院分区：
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作者：
A. Barman;V. Kruglyak;R. Hicken;A. Kundrotaitė;M. Rahman
用时间分辨扫描克尔效应显微镜研究了方形Ni81Fe19元件的小振幅磁化进动。在元件的中心放置一个直径1mm的探针点，观察到一个单一的岁差模式。利用相干旋转模型，推导出了约30 Oe的四倍各向异性的存在。时间分辨图像表明，动态磁化最初在元件边缘是不均匀的，然后向中心扩展。在测量时间内，元件中心的动态磁化是均匀的，证明了在分析进动频率时使用相干旋转模型是合理的。
We have studied small amplitude magnetisation precession in a square Ni81Fe19 element by time resolved scanning Kerr effect microscopy. A single precessional mode was observed with a 1mm diameter probe spot placed at the centre of the element. Using a coherent rotation model, the presence of a four-fold anisotropy of about 30 Oe was deduced. Time resolved images show that the dynamic magnetisation is initially nonuniform at the edges of the element, with the nonuniformity then extending towards the centre. The dynamic magnetisation is uniform at the centre of the element over the measurement time, justifying the use of the coherent rotation model in the analysis of the precession frequency.