自旋转矩效应和Rashba效应所驱动的磁畴壁动力学研究

项目名称： 自旋转矩效应和Rashba效应所驱动的磁畴壁动力学研究

项目编号： No.11274241

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 刘要稳

作者单位： 同济大学

项目金额： 70万元

中文摘要： "自旋转矩（STT）效应"打破了"磁场"操控磁化矢量的传统模式，开创性地提出在纳米自旋电子器件中采用自旋极化电流直接操控磁矩方向，近些年已引起广泛关注。与之相对应，2010年在结构反演非对称(SIA)磁纳米线中新发现的电流诱导的"Rashba效应"是电流调控磁矩转动的又一个关键因素，对开发基于电流驱动磁畴壁移动机理的赛道磁存储器和自旋逻辑器件至关重要。然而有关Rashba效应的物理机理、特性和作用等基础性研究才刚刚起步，亟待深入探讨。本课题拟发展和建立STT效应和Rashba效应并存的 微磁学模型，采用微磁学方法，研究两者关联机制；探讨磁畴壁移动速度与Rashba效应、STT效应、阻尼因子等参数依赖性；揭示Rashba效应驱动不同类型磁畴壁结构（Bloch壁、Neel壁、磁涡旋壁等）的行为特性和规律；进而理论优化磁纳米线器件结构，为发展电流直接驱动的新型自旋电子器件奠定基础。

中文关键词： 微磁学；自旋转矩效应；Rashba效应；磁性隧道结；磁动力学

英文摘要： The spin-transfer torque (STT) effect has attracted great attention in the past several years, in which the orientation of magnetization in nanoscale spintronic devices can be controlled by a spin-polarized current, instead of the conventional magnetic fields. In contrast, the current-mediated Rashba effect in magnetic nanowires with a structural inversion asymmetry (SIA) has recently been reported, which has been suggested to be another key concept for the successful applications in the nonvolatile Race-track memory and spin logic devices based on the controlled movement of domain walls. However, the topic of current-induced Rashba effect in magnetic nanowires only started with two 'Nature Materials' papers published in last year, and so the topic is absolutely novel and many aspects are still unclear. In this project, micromagnetic simulation technique will be employed to study the combined effects of both STT and Rashba in magnetic nanowires caused by spin-polarized current. Firstly, the micromagnetic model of the two effects will be developed. Secondly the influence of Rashba effect, STT and damping factor on the domain-wall velocity will be clarified. Furthermore, the characteristics and varying trends in different types of domain walls including Bloch, Neel and vortex walls will be explored. And finally th

英文关键词： Micromagnetic simulation；spin-transfer torque；Rashba effect；magnetic tunnel junction；Mangetization dynamics