标题： 超快自旋积累驱动多层结构中的磁化反转 显示英文标题

标题： Ultrafast Spin Accumulations Drive Magnetization Reversal in Multilayers

摘要： 在自旋电子器件中，对飞秒时间尺度上的热量和自旋传输进行工程设计和控制，为以前所未有的速度操控磁化开辟了新途径。然而，由于探测超快、非平衡自旋动力学的挑战，其潜在的反转机制仍知之甚少。在本研究中，我们证明典型的磁光实验可以被利用来获取在超快激光激发后磁性多层结构中产生的自旋积累的时间演化。此外，我们的分析表明，自旋阀中自由层的最终磁态主要由参考层磁化的超快动力学决定。我们的结果解耦了多层堆栈中的磁化和自旋传输动力学，并确定了去磁化和再磁化驱动的自旋积累是全光切换的关键机制。这些发现建立了基于定制自旋电流工程的超快自旋电子器件的新设计原则。 显示英文摘要

摘要： Engineering and controlling heat and spin transport on the femtosecond time-scale in spintronic devices opens up new ways to manipulate magnetization with unprecedented speed. Yet the underlying reversal mechanisms remain poorly understood due to the challenges of probing ultrafast, non-equilibrium spin dynamics. In this study, we demonstrate that typical magneto-optical experiments can be leveraged to access the time evolution of the spin accumulation generated within a magnetic multilayer following an ultrafast laser excitation. Furthermore, our analysis shows that the final magnetic state of the free-layer in a spin-valve is mainly dictated by the ultrafast dynamics of the reference-layer magnetization. Our results disentangle magnetization and spin transport dynamics within a multilayer stack and identify demagnetization and remagnetization-driven spin accumulation as the key mechanism for all-optical switching. These findings establish new design principles for ultrafast spintronic devices based on tailored spin current engineering.