All-Optical Helicity-Dependent Switching in Hybrid Metal-Ferromagnet Thin Films
All-Optical Helicity-Dependent Switching in Hybrid Metal-Ferromagnet Thin Films
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DOI：
10.1002/adom.202000379
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发表时间：
2020-05-04
影响因子：
9
通讯作者：
Liu, Yongmin
中科院分区：
文献类型：
--
作者：
Cheng, Feng;Du, Zhidong;Liu, Yongmin
在过去的几十年里，超快激光脉冲对磁化的光学操纵引起了广泛的兴趣。它不仅展示了自旋、电子、声子和光子之间相互作用产生的有趣的基础科学，而且还显示了以比当前技术快三个数量级的速度处理和存储数据的潜力。本文实验证明了Co/Pt多层垂直磁各向异性复合金属-铁磁体薄膜的全光螺旋相关开关（AO-HDS）。系统地研究了Co/Pt-Au杂化材料在不同激光重复率、扫描速度和频率下的开关行为。与裸露的Co/Pt多层膜相比，当沿扫描方向每μ m的激光脉冲数逐渐增加时，金属-铁磁体杂化薄膜表现出明显的AO-HDS。此外，AO-HDS效应对激光的影响非常强。基于光磁耦合模型的数值模拟，进一步提出了一种可能的机理。这些发现预示着一种新的材料体系能够表现出稳定的AO-HDS现象，因此可以改变未来的磁存储设备，特别是添加由贵金属制成的等离子体纳米结构。
Over the past decades, optical manipulation of magnetization by ultrafast laser pulses has attracted extensive interest. It not only shows intriguing fundamental science arising from the interactions between spins, electrons, phonons, and photons, but also manifests the potential to process and store data at a speed that is three orders of magnitude faster than the current technologies. In this paper, all-optical helicity-dependent switching (AO-HDS) in hybrid metal-ferromagnet thin films, which consist of Co/Pt multilayers with perpendicular magnetic anisotropy and an Au film capping layer on the top, is experimentally demonstrated. The switching behaviors of the hybrid Co/Pt-Au material, with various laser repetition rates, scanning speeds, and fluencies, are systematically studied. In comparison with bare Co/Pt multilayers, the hybrid metal-ferromagnet thin films show pronounced AO-HDS when the number of laser pulses per mu m along the scanning direction gradually increases. In addition, the AO-HDS effect is very robust against laser fluences. A possible mechanism is further proposed based on numerical simulations of the optomagnetic coupling model. These findings promise a new material system that exhibits stable AO-HDS phenomena, and hence can transform future magnetic storage devices, especially with the addition of plasmonic nanostructures made of noble metals.