垂直Co/Pt多层膜和TbFeCo薄膜中的旋性依赖全光磁翻转的研究

磁性材料中的全光磁翻转是自旋电子学领域的前沿研究方向之一，旋性依赖全光磁翻转的物理机制尚不清楚，探索更多的全光磁翻转材料是长期持续的目标。本项目拟通过磁控溅射和分子束外延手段制备高质量磁性薄膜。重点研究铁磁Co/Pt多层膜和亚铁磁TbFeCo薄膜中的旋性依赖全光磁翻转过程。利用双泵浦技术和元素分辨技术定量地研究全光翻转过程中的纯热与旋性效应。通过调控材料的物理性能包括磁阻尼、补偿温度和居里温度等，探究决定全光磁翻转的关键物理参数。通过调控双泵浦激光脉冲的脉冲宽度、时间间隔等参数研究材料全光磁翻转的动力学过程。阐明反法拉第效应和磁圆二色向性在全光磁翻转中发挥的作用，有望解决长久以来物理机制上的学术争议。在此基础上本项目还将探索更多可能发生旋性依赖全光磁翻转的新材料，主要探究自旋电子学领域的重要垂直磁化材料。本项目将为全光磁翻转在新一代自旋电子器件中的应用打下基础。

All-optical magnetic switching in magnetic materials is one of the forefront topics of spintronics. The underlying mechanism of helicity-dependent all-optical switching is still unclear and to discover more applicable magnetic material for all-optical switching is a long-term objective. This project will start from the growth of high-quality magnetic thin films using magnetron sputtering and molecular beam epitaxy techniques. This project will focus on investigating the helicity-dependent all-optical switching in ferromagnetic Co/Pt multilayer structures and the ferrimagnetic TbFeCo thin films. Using the dual-pump and element-resolved techniques, the pure heating and helicity-dependent effects will be quantitatively studied. It is aimed to figure out the key parameters which determine the all-optical switching by tuning the physical characteristics of the magnetic materials, including magnetic damping, compensation temperature, Curie temperature, etc. By controlling the pulse width of the dual-pump and the delay time between them, the spin dynamics during the all-optical switching will be investigated. Revealing the roles of inverse Faraday effect and magnetic circular dichroism in helicity-dependent all-optical switching is a main target, which may resolve the debate regarding the underlying mechanisms. Seeking for more applicable magnetic materials for helicity-dependent all-optical switching is another important task in this project, which will focus on the important perpendicular magnetized materials in spintronics. This project will lay solid foundation for the future application of all-optical magnetic switching in the next-generation spintronic devices.