“YIG/金属”异质纳米薄膜自旋输运过程中多重物理机制纠缠的研究

“铁磁绝缘体YIG/金属”异质纳米薄膜的自旋输运过程，纯自旋流效应、磁近邻效应、界面Rashba自旋-轨道耦合效应多重物理机制纠缠不清且存在重大争议，具有丰富的物理内涵，是近年来新兴绝缘体自旋电子学领域的研究热点。本项目围绕“YIG/金属”异质结构薄膜，利用先进的热电、低噪音磁阻、电场调制等输运表征手段，全面系统研究金属材料的不同自旋-轨道耦合强度和电子结构等因素对“YIG/金属”中所呈现相关物理机制的影响与规律；掌握磁近邻效应、界面Rashba自旋-轨道耦合效应发生的基本条件、随薄膜厚度的变化特点及对纯自旋流效应的影响规律，力求定量区分多重物理机制的各自贡献大小，发展定量化自旋霍尔角、自旋扩散长度等自旋流关键参量值的方法；在深刻理解磁近邻效应、界面Rashba自旋-轨道耦合效应微观机理的基础上，积极探索拓展自旋相关的热电材料体系，提升优化重要的应用技术参数，推进自旋热电器件的实用化进程。

Pure spin current effect, magnetic proximity effect as well as interficial Rashba spin-orbit coupling effect have been tightly intertwined and greatly debated in the spin-dependent transport processes of "ferromagnetic insulator YIG/metal" heterostructure nanometer films,which exhibits abundant physical connotation and has become one of the hotspots for research in the rapidly developing insulator spintronics.In this proposal, we will take advantage of our state of the art thermoelectricity,low-noise magnetoresistance, electric-field modulation and other transport measurements to systematically characterize the spin-dependent transport properties of "YIG/metal" heterostructure nanometer films. We will firstly study the effect of the spin-orbit coupling, electronic structure and other factors on the emerging related physical mechanisms.Then, we will investigate the prerequisite for magnetic proximity effect and interfical Rashba spin-orbit coupling effect, find out the thickness-dependent features for magnetic proximity effect and interfical Rashba spin-orbit coupling effect, and confirm that how magnetic proximity effect and interfical Rashba spin-orbit coupling effect can influence pure spin current effect. We will also pursue to separate individual contribution from the magnetic proximity effect, interficial Rashba spin-orbit coupling effect and pure spin current effect, and try to search the methods to quantify the key parameters of spin current including spin Hall angle as well as spin diffusion length.On the basis of deep understanding of the microscopic mechanisms，we will actively explore spin-related thermoelectric material systems，promote the important parameters for application，and further advance the practical process of spin-related thermoelectric devices.