石墨烯边缘化磁性碳膜的可控生长及其自旋式磁传感机理研究

In recent years, by introducing graphene edge spin-electron interactions as sensitive principles, the next generation nano spin-magnetic sensor has been rapidly developed. However, the spin-electron interacting mechanisms under different structural features (such as scales, forms) are not clear yet, which have become the bottleneck of the development of such new nano device. Therefore, based on his earlier work at the controllable manufacture of graphene-edged carbon film and their magnetoresistance origins, the applicant proposed the scientific problem of "Spin-magnetic sensing mechanism based on graphene edged magnetic carbon film", integrating the process of graphene growth and edge fabrication, directly growing three types of graphene edge structures which are through structure, dispersing structure and sandwich structure. Magnetic environment Raman spectroscope, magnetic force scanning tunneling microscope are used to reveal the spin orientation under external magnetic field. Physical property measurement system is used to investigate the modulating mechanisms on the transport of itinerary electrons. Systemically explain the deflecting (Hall voltage), scattering (magnetoresistance) and tunneling (magneto tunneling current) of in three types of graphene edged films, and build sensor prototypes based on the above sensing mechanisms. The research outcome has important scientific significance for systemically understanding the edge scale-effect on the spin magnetic sensing mechanisms, and provide support for the scientifically design and manufacture of new spin nano magnetic sensors.

近年来，以石墨烯边缘电子自旋在磁场下改变巡游电子传输特性为原理的下一代自旋式磁传感器引起了极大关注。然而不同石墨烯边缘形态（如尺寸、间距）下的电子自旋作用机制目前尚未明确，成为这一新型纳米传感器发展的瓶颈。为此，申请人基于石墨烯边缘化碳膜可控制造及其磁阻效应起源的工作基础，提出“石墨烯边缘化磁性碳膜的自旋式磁传感机理”这一科学问题，将石墨烯“生长”与“边缘化”集成，进行连续式、分散式、夹层式三种石墨烯边缘化碳膜的可控制造，借助磁力隧道显微镜，磁场拉曼光谱，综合物性测量仪等手段揭示磁场下石墨烯边缘电子自旋的取向规律，探究其对巡游电子运动的调控机制，系统阐明三种形态石墨烯边缘中的巡游电子偏转（霍尔电压），散射（磁致电阻）与隧穿（磁致隧穿电流）效应，并以此为传感机理分别构造敏感元件。该研究对于揭示石墨烯边缘尺度效应下的自旋磁传感本质有重要科学意义，将为新型碳基磁传感器的科学设计与制造提供支持。

根据项目计划书内容，本项目围绕“石墨烯边缘化磁性碳膜的自旋式磁传感机理”这一核心科学问题展开，研究内容有三：（1）连续式石墨烯边缘自旋内磁场对霍尔效应的增强机理；（2）分散式石墨烯边缘自旋散射作用下的磁致电阻效应；（3）夹层式石墨烯边缘自旋诱导下的磁致隧穿效应。执行期内取得主要研究进展如下：.1. 阐明了连续式石墨烯边缘强磁性与纵向导电能力的协同优化作用，以此为基础研发室温霍尔式传感器件，磁场分辨能力0.001T，角度分辨能力2°，工作温度范围250-400 K，相关成果发表SCI论文2篇，授权发明专利1项。.2. 揭示了分散式石墨烯边缘自旋过滤、波函数收缩、洛伦兹力偏转等磁阻效应起源的竞争机制，实现了纳晶尺寸在3.7~10.5nm可调控制造，最大室温磁阻效应超过10%。以此为基础研发室温自旋式整流开关器件，磁阻效应开关比达到1000%，相关成果发表SCI论文2篇，授权发明专利1项。.3. 澄清了夹层式石墨烯纳晶边缘诱导高迁移率通道效应，及其对面内异质结构磁阻效应增强机理，室温磁阻效应提高8倍。提出了化学气相沉积中的电子照射制造原理，获得了站立式石墨烯纳米片结构，搭建了石墨烯边缘自旋极化传感测试平台，相关成果发表SCI论文1篇，授权发明专利2项。.此外，本研究取得的关键数据（待发表）有：.1. XMCD表征发现石墨烯纳晶碳膜室温具有铁磁性，现有数据中差谱强度0.005，对应磁性大约是Ni的1%。SQUID表征测得饱和磁化强度为4.6emu/g，与XMCD测得磁性强度匹配。上述结果已在合肥光源和上海光源重现。.2. 在石墨烯纳晶结构中发现自旋输运行为，包括自旋塞贝克效应SSE，自旋霍尔磁阻效应SMR，两种输运行为的温度依赖性一致，表明是GNC结构固有性质。.以上数据目前在整理汇总中，拟投稿Nature期刊。.执行期内共计发表SCI代表作5篇，授权发明专利4项，发表国际会议报告6篇。依托研究结果获得省部级科技奖励各1项，市级科技奖励1项。培养研究生12人。