芯壳结构的内部填充铁磁金属晶体的碳基材料的磁电输运与自旋调控研究

Recently spintronics in layered planar (LP) structures of ferromagnetic metal/nonmagnetic (F/N) material systems has been extensively studied owing to its importance to the design, fabrication and application of new types of spintronic devices. However, both the instability of the F/N interfaces when exposed to oxygenated environments for long and the integrated difficulty due to the complicated multiple-step micro-nanofabrication of the system challenge the researchers of the LP structures. On the other hand, core/shell (CS) structures of ferromagnetic metallic crystal-filled carbon-based materials (FMC-CBMs) can solve these problems in LP structures, because the F/N interfaces inside can be well protected by robust walls of CNTs and because they can be synthesized by in-situ growth. Meanwhile, metal inside the FMC-CBMS are ferromagnetic , carbon tube's surface curvature results in spin-orbit coupling effect and the spin diffusion length in CNTs can last over microns, providing a solid platform for spin manipulation. To the best of our knowledge, so far no systematic study of spin-dependent properties, such as magneto-transport and spin manipulation in FMC-CNTs, has been reported. In this proposal, based on our previous experimental work in FMC-CBMs, we plan to obtain different kinds of FMC-CBMs by optimizing growth conditions of chemical vapor deposition, study the structures and spin-dependent properties of the systems for development of spintronic materials and applications of spintronic devices in the future.

近年来层状平面结构的铁磁金属/非磁材料体系的研究深受关注，因其可对新型自旋电子材料与器件的设计、制备和应用产生重要影响. 然而，层状平面结构所需的多步复杂生长制备工艺，以及铁磁/非磁界面在含氧环境中的稳定性问题，给研究者们提出了重大挑战. 芯/壳结构的铁磁金属晶体填充的碳基材料（碳纳米管、巴基纸与碳泡沫等）可望解决层状平面结构面临的问题, 因为此体系可原位生长获得，且碳壁为内部界面提供良好保护. 并且，内部填充金属具铁磁性，碳管因表面曲率具有较强电子自旋轨道耦合作用，同时自旋扩散长度可达微米量级，体系具备自旋调控的物理基础. 然而，目前罕见芯/壳结构碳基材料的磁电输运与自旋调控特性的研究. 本项目拟基于研究组前期实验工作，生长获得所需的不同种类铁磁金属晶体填充的碳基材料，分析其结构与基本物性，在此基础上对其自旋相关特性进行系统深入研究，以期为碳基自旋电子材料开发与器件应用提供重要参考.

本项目采用化学气相沉积法制备各种类型的碳基包裹磁性晶体复合体系样品，并进而研究其磁电光等物理性质，并对其自旋相关性质进行测试与调控。取得的主要结果总结如下：（一）通过系统摸索化学气相沉积法工艺条件，制备出了形貌各异的铁磁晶体填充的碳基材料，如不同长度和不同厚度的碳纳米管包裹的不同长度的铁磁晶体纳米线复合结构，层状石墨结构包裹的铁磁晶体复合结构等，为制备基于不同形貌的碳基复合结构提供有益的参考。（二）通过测试不同种类的包裹铁磁晶体的碳纳米管复合薄膜和单根碳纳米线复合结构，发现了不同形貌不同缺陷的铁磁晶体/碳纳米管复合结构中磁电输运的规律，揭示了输运性质和复合体系结构与成分之间的关系，有望用于基于碳纳米管的电子器件与磁存储器件。（三）通过采用第一性原理计算方法等计算和理论分析方法，阐述了非磁性原子与碳纳米管复合体系产生磁性的机理，也对包裹磁性晶体的碳纳米管的磁电输运机理做出了解释。本项目的主要成果对于加深对有关低维碳基复合材料基本物性的理解和拓展低维碳基复合材料在电子器件和自旋电子器件方面的应用，具有参考价值。