Nonequilibrium sub-10 nm spin-wave soliton formation in FePt nanoparticles
Nonequilibrium sub-10 nm spin-wave soliton formation in FePt nanoparticles
复制标题
FePt 纳米颗粒中非平衡亚 10 nm 自旋波孤子形成
DOI：
10.1126/sciadv.abn0523
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发表时间：
2022
期刊：
影响因子：
13.6
通讯作者：
Xiaocui Wang et al.
中科院分区：
文献类型：
--
作者：
Diego Turenne;Alexander Yaroslavtsev;Xiaocui Wang et al.
磁性纳米颗粒，如L10相的FePt，是我们目前数据存储技术的基石。随着晶粒变得越来越小以满足技术需求，超顺磁性极限要求材料具有更高的磁晶各向异性。这反过来又将磁交换长度减少到仅几纳米，从而能够在纳米颗粒内诱导磁性结构。在这里，我们描述了自旋波孤子的存在，自旋波激发的动态局域束缚态，在FePt纳米粒子。我们用时间分辨的X射线衍射和微磁模型表明，在飞秒激光激发下，亚10 nm大小的自旋波孤子形成于去磁状态。测得的孤子自旋进动频率为0.1太赫兹的位置，该系统作为一个平台，开发新型的微型器件。
Magnetic nanoparticles such as FePt in the L10phase are the bedrock of our current data storage technology. As the grains become smaller to keep up with technological demands, the superparamagnetic limit calls for materials with higher magnetocrystalline anisotropy. This, in turn, reduces the magnetic exchange length to just a few nanometers, enabling magnetic structures to be induced within the nanoparticles. Here, we describe the existence of spin-wave solitons, dynamic localized bound states of spin-wave excitations, in FePt nanoparticles. We show with time-resolved x-ray diffraction and micromagnetic modeling that spin-wave solitons of sub–10 nm sizes form out of the demagnetized state following femtosecond laser excitation. The measured soliton spin precession frequency of 0.1 THz positions this system as a platform to develop novel miniature devices.