垂直磁化纳米线中的畴壁钉扎与去钉扎动力学研究

项目名称： 垂直磁化纳米线中的畴壁钉扎与去钉扎动力学研究

项目编号： No.11474225

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 熊锐

作者单位： 武汉大学

项目金额： 98万元

中文摘要： 钉扎和去钉扎是磁纳米线中畴壁运动重要的过程。垂直磁化纳米线中的畴壁宽度小且结构稳定，对垂直磁化纳米线中畴壁钉扎与去钉扎过程及相关动力学的研究一方面有助于掌握磁纳米线畴壁运动的规律和操控方法，从而为实现逻辑运算和高密度存储奠定基础，另一方面，可以探索自旋转移力矩中非绝热项的本质等一些基本科学问题。本项目将以具有垂直各向异性的FePt和CoPt合金为材料体系, 研究纳米线中畴壁钉扎与去钉扎过程中畴壁的运动状态、去钉扎场大小以及它们与纳米线和钉扎点的几何尺寸等因素的关系，探索有效调控畴壁钉扎与去钉扎行为的方法；研究不同各向异性纳米线中非绝热系数及阻尼系数，澄清二者与自旋轨道耦合强弱的关系，并在此基础上结合理论研究探索二者的物理本质。

中文关键词： 自旋电子学；磁纳米线；磁畴壁；自旋转移矩；钉扎

英文摘要： Investigation of pinning and depinning processes of domain wall(DW)in magntic nanowire is of great importance from view points of both fundamental physics and applications (DW based logic and storage devices ).Due to the narrower DWs which have a simpler and more rigid internal Bloch/Neel DW structure and the expected higher spin transfer efficiency in them, perpendicular magnetized nanowires are not only more attractive in application but also of greater advantage for understanding the mechanic of spin transfer and origin of non-adiabatic term as well as magnetic damping during DW motion.In this project, the research will focus on the study of pinning and depinning dynamics of DW in perpendicular magnetized nanowires of FePt and CoPt alloys. By controlling the order parameter and composition of the alloys, the strength of spin-orbital coupling in the nanowire will be adjusted.The dependence of DW pinning and depinning behaviors and depinning field on current density as well as geometry of the nanowires and the artifical defect will be investigated by experiment and micromagnetic simulation.The damping constant α and nonadiabatic constant β of each will be extracted by using the one dimensional model as well as by miromagnetic simulation; the relation between α and β as well as their dependence on the strength of spin-orbital coupling will be clarified based on the experimental results and first principle calculations; The origins of α and β will be investigated by theoretical study.

英文关键词： spintronics;magnetic nanowires;magnetic domain;spin transfer toque;pining