磁性异质结中自旋轨道矩的物理机制研究

磁性异质结中自旋轨道矩为电流驱动磁矩翻转提供了一种全新的手段，被视为继巨磁电阻和自旋转移矩效应之后自旋电子学最重大的发现之一。当前对于自旋轨道矩两个可能的物理机制：体自旋霍尔效应和界面Rashba效应尚存在极大争议。本项目拟通过测量高灵敏度交流谐振电压及自旋矩铁磁共振等手段，围绕非磁层/磁性层异质结中的自旋轨道矩，从以下几个方面开展研究：（1）膜厚研究：从不同的厚度依赖关系上，分析其中可能占主导的物理机制。（2）界面掺杂：通过界面掺杂探索及实现界面Rashba效应占主导的自旋轨道矩。（3）物理表征：进一步研究自旋轨道矩在不同物理维度下（温度和磁矩方向等）的物理特性，量化体自旋霍尔效应和界面Rashba效应的贡献。本项目有望全面揭示磁性异质结自旋轨道矩的物理机制，这将有助于探索与自旋轨道矩相关的新现象和新机制、推进其在新一代自旋电子学器件中的应用。

Spin orbit torque (SOT) in magnetic heterostructures provides a new route to switch the magnetization electrically, which is one of the most significant development in spintronics after giant magnetoresistance and spin transfer torque. However, the possible physical origin of SOT, either bulk spin Hall effect or interfacial Rashba effect, is still under intense debate. This project will study the SOT in magnetic heterostructures by measuring ac harmonic voltage with high sensitivity and spin-torque ferromagnetic resonance. While this project aims to reveal the physical origin of SOT in nonmagnetic metal/ferromagnet heterostructures, it will be realized as follows: (1) Thickness dependence studies: Identify the dominant physical origin of SOT from thickness dependence study. (2) Interface doping: Realization and exploration of interfacial Rashba effect dominated SOT. (3) Physical characterization: Quantifying bulk spin Hall effect contribution and interfacial Rashba effect contribution from further studies by varying various physical parameters, such as temperature and magnetization direction. By illustrating a comprehensive physical picture of SOT, this project will contribute in exploring novel features of magnetic heterostructures and allow a full control of SOT for new generation spintronic devices.