Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India.
ACS Nano. 2011 Dec 27;5(12):9559-65. doi: 10.1021/nn202791g. Epub 2011 Nov 4.
We report an all-optical time-domain detection of picosecond magnetization dynamics of arrays of 50 nm Ni(80)Fe(20) (permalloy) dots down to the single nanodot regime. In the single nanodot regime the dynamics reveals one dominant resonant mode corresponding to the edge mode of the 50 nm dot with slightly higher damping than that of the unpatterned thin film. With the increase in areal density of the array both the precession frequency and damping increase significantly due to the increase in magnetostatic interactions between the nanodots, and a mode splitting and sudden jump in apparent damping are observed at an edge-to-edge separation of 50 nm.
我们报告了一种全光时域检测技术，用于探测 50nm 的 Ni(80)Fe(20)（坡莫合金）点阵列的皮秒级磁化动力学，其探测范围可低至单个纳米点。在单个纳米点的范围内，动力学显示出一个主要的共振模式，对应于 50nm 点的边缘模式，其阻尼略高于未图案化的薄膜。随着阵列的面密度增加，由于纳米点之间的静磁相互作用的增加，进动频率和阻尼都显著增加，并且在边缘到边缘的间隔为 50nm 时观察到模式分裂和明显阻尼的突然跳跃。
