近年来具有垂直磁各向异性的交换耦合复合薄膜体系由于在信息存储领域的巨大应用前景而备受关注，它不仅是发展下一代超高密度磁硬盘介质材料的合适结构，而且可以有效解决自旋转矩型磁随机存储器存储单元尺寸减小时热稳定性变差的问题。深入理解并掌握垂直复杂磁性体系的超快磁动力学特性，对提高信息存取速度和存储密度、降低能耗至关重要。本课题拟采用时间分辨的磁光克尔效应激光泵浦探测技术，辅之以微磁学模拟分析，系统研究垂直磁化交换耦合复杂体系中耦合强度、耦合类型、垂直各向异性能和材料结构等因素对激光诱导超快磁动力学行为过程的影响；认识磁矩运动的特征和变化规律，揭示影响超快退磁、磁弛豫恢复、进动翻转和阻尼因子的物理机制；实现对复杂垂直耦合薄膜体系材料结构及其性能的调控和优化，为发展高性能磁存储设备奠定基础。

In recent years exchange-coupled composite magnetic thin film system with perpendicular magnetic anisotropy (PMA) has attracted great attention, since they are not only considered as the suitable media material structure for ultra-high density magnetic hard disk, but also can effectively solve the issue of thermal stability degradation as the cell size of STT-MRAM shrinks. Deep understanding and controll of ultrafast magnetization dynamics for such magnetic composite structures are of key importance for fast read/write speed, high storage density and low power consumption. In this project by using the time-resolved femto-second laser pump-probe technique based on the magneto-optical Kerr effect and micromagnetic simulation, we plan to systematically investigate the influence of exchange coupling strength, exchange coupling type, PMA strength, and material structure on the laser-induced ultrafast magnetization behaviors. We aim to gain a deep insight into the characteristics and varying trend of magnetization motion, uncover the physical mechanism for ultrafast demagnetization, magnetization relaxation, magnetic precession and damping, and achieve structural optimization as well as material property manipulation for practical applications in high-performance magnetic storage devices.