自旋轨道转矩诱导磁化反转动力学行为的电镜原位研究

Spin-Orbit Torque （SOT） provides a new way to develop low energy consumption, high speed, and high density for nonvolatile electronic devices. Nevertheless, the physics of the SOT-induced magnetization dynamics is still not fully understood, and the memory architecture is still at its infancy stage. This project is aimed to intuitively research SOT-induced magnetization reversal mechanism in nanoscale. morphology- and structure-controlled magneto-nanostructured cell will be prepared by means of a jointed method involved to magnetron sputtering, micro-nano processing technology and focused ion beam etching techniques. in-situ electron microscopy techniques is used to real-timely observe and record in-situ spherical aberration correction transmission electron microscope (EM) equipped with lorentz prism and the electron holographic, meanwhile, combined with loading technique about the electric field and the magnetic field in-situ EM, Ultra-high speed image acquisition system and electron energy-loss spectroscopy, the detailed and dynamic image information for SOT-induced magnetization dynamics in magneto-nanostructured cell are obtained，and the physical mechanism of SOT-induced magnetization dynamics is studied. Those research results will provide true and reliable information and guidance to development of high-performance magentic memory.

自旋轨道转矩为研发低能耗、高速度、高密度的非失忆性电子器件提供了一条全新的途径，然而到目前为止对其的研究还处于初始阶段而且其物理过程的理解还不是非常清晰。本项目拟通过磁控溅射、微纳加工技术结合聚焦离子束电镜刻蚀技术制备不同形貌、尺度和结构的具有SOT效应的微纳米磁结构单体，利用配置了洛仑兹棱镜、电子全息的球差矫正透射电镜，结合原位电场、磁场加载技术，借助超高速图像采集系统和电子能量损失谱，原位实时动态化的观察和记录具有SOT的纳米磁结构中电流驱动的磁畴移动和磁化反转的详细动态信息，探索具有SOT的纳米磁结构中电流驱动磁化动力学的物理学机制, 为研发高性能磁存储器提供真实可靠的信息和指导。

电流在强自旋轨道耦合材料中的自旋轨道力矩(SOT)可以超快、高效和低能耗的操纵磁矩，为研发新一代自旋逻辑器件和自旋存储器件提供了重要物理基础，将该效应应用于当前自旋电子学金属多层膜器件的前提是寻找具有大自旋霍尔角,高导电性和高电荷-自旋转换效率的材料。基于此，本项目以[Pt/Co/Ta]n磁性多层薄膜和PtTe2/Py异质结为研究对象，系统研究了形貌、厚度和成份对SOT诱导磁化反转的影响规律、动态磁化过程和PtTe2薄膜产生SOT可能来源的物理机制。同时，我们通过改变Co层和PtTe2的厚度参数，实现了纳米磁结构的调控，在电镜原位实时动态地研究了[Pt/Co/Ta]n中条纹畴的运动和外磁场关系，以及PtTe2的自旋霍尔角、自旋霍尔电导和电流-自旋流转换效率。发现了PtTe2比Pt具有更大的自旋霍尔角和更高的导电特性，拓展了制备自旋电子学器件的材料。