Wang Chuangtang, Liu Yongmin
Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, 02115, USA.
Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, 02115, USA.
Nano Converg. 2020 Nov 10;7(1):35. doi: 10.1186/s40580-020-00246-3.
The interaction between ultrafast lasers and magnetic materials is an appealing topic. It not only involves interesting fundamental questions that remain inconclusive and hence need further investigation, but also has the potential to revolutionize data storage technologies because such an opto-magnetic interaction provides an ultrafast and energy-efficient means to control magnetization. Fruitful progress has been made in this area over the past quarter century. In this paper, we review the state-of-the-art experimental and theoretical studies on magnetization dynamics and switching in ferromagnetic materials that are induced by ultrafast lasers. We start by describing the physical mechanisms of ultrafast demagnetization based on different experimental observations and theoretical methods. Both the spin-flip scattering theory and the superdiffusive spin transport model will be discussed in detail. Then, we will discuss laser-induced torques and resultant magnetization dynamics in ferromagnetic materials. Recent developments of all-optical switching (AOS) of ferromagnetic materials towards ultrafast magnetic storage and memory will also be reviewed, followed by the perspectives on the challenges and future directions in this emerging area.
超快激光与磁性材料之间的相互作用是一个引人关注的课题。它不仅涉及一些有趣的基本问题，这些问题尚无定论，因此需要进一步研究，而且还具有革新数据存储技术的潜力，因为这种光磁相互作用提供了一种超快且节能的控制磁化的手段。在过去的四分之一个世纪里，该领域已经取得了丰硕的进展。在本文中，我们回顾了关于超快激光诱导铁磁材料中磁化动力学和开关特性的最新实验和理论研究。我们首先基于不同的实验观察和理论方法描述超快退磁的物理机制。自旋翻转散射理论和超扩散自旋输运模型都将被详细讨论。然后，我们将讨论铁磁材料中的激光诱导转矩以及由此产生的磁化动力学。还将回顾铁磁材料全光开关（AOS）在超快磁存储和记忆方面的最新进展，随后是对这个新兴领域中挑战和未来方向的展望。
