SiC基半导体室温铁磁性的机理及其对电输运、光学特性的影响

This project is aimed to research room temperature ferromagnetism mechanism of SiC-based diluted magnetic semiconductors and the effects of ferromagnetism on electrical transport and optical properties. The key point is to study the origin of magnetic moment, the interaction between magnetic moments, and the magnetic anisotropy of room temperature ferromagnetism. We will investigate how ferromagnetism in SiC-based diluted magnetic semiconductors is influenced by vacancy and carrier. In order to regulate the magnetic behaviour, the fabrication process will be optimized and the mechanism causing magnetism in this type of substance will be explored. The methods to be used are liquid exfoliation and radio-frequency magnetron sputtering. Through magnetic measurements, microstructure, optical and electrical properties analysis, we want to confirm the intrinsic characteristics of room temperature ferromagnetism for the SiC-based diluted magnetic semiconductors. Furthermore, the relevant relationship between the occurrence of ferromagnetism and the defect or carrier concentration, type of defect, carrier and phase structure in the samples is going to be investigated. Combined first-principle calculation results, the origin of microscopic magnetic moment and interaction between magnetic moment in SiC-based diluted magnetic semiconductor will be explored. Analyzing the electron spin resonance and magnetic spectrum measurements, this research will reveal the mechanism of magnetic anisotropy behind their stable room temperature ferromagnetism. Combining the above results, the mechanism of ferromagnetism in SiC-based diluted magnetic semiconductors will be illuminated. On the basis of realization controllable ferromagnetism, the effect of ferromagnetism on electrical transport and optical property is further study. The outcomes of this project will provide the theoretical and experimental gist for multifunctional spintronic devices integrated optics and electromagnetism.

本项目以研究SiC基稀磁半导体室温铁磁性的机理，以及铁磁性与电输运和光学特性的相关规律为目的，以探索产生室温铁磁性的微观磁矩起源、磁矩间相互作用及其室温下稳定的各向异性特征为关键展开研究。拟分别采用液相剥离法和磁控溅射法制备SiC基稀磁半导体材料，探索由缺陷或载流子诱导室温铁磁性的制备工艺。通过宏观与微观磁性、微结构及光电特性分析，获得缺陷或载流子类型及浓度与其铁磁性的相关规律，结合第一性原理计算，探究SiC基稀磁半导体铁磁性的微观磁矩起源及磁矩间相互作用。利用电子自旋共振和磁谱测量，研究其在室温下具有稳定铁磁性的各向异性机制。结合以上数据和理论分析，获得SiC基稀磁半导体室温铁磁性的机理。在实现铁磁性可控的基础上，进一步研究SiC基稀磁半导体的电输运和光学特性随铁磁性的变化规律，为实现其在集光电磁一体化多功能自旋电子器件中的应用提供理论依据和实验基础。

SiC稀磁半导体兼具铁磁性和优异的半导体性质，在未来自旋电子器件中有广泛的应用前景。但是，在SiC稀磁半导体中，铁磁性的起源仍有很大争议，因此，深入理解SiC稀磁半导体的铁磁性机理，实现铁磁性的调控，是实现SiC稀磁半导体材料在多功能自旋电子器件应用中拟解决的关键问题。.本项目以研究SiC稀磁半导体材料在低维下表现出的铁磁性机制为目的，以探索产生铁磁性的微观磁矩起源为关键展开研究，得到了以下结论：首先，我们采用液相剥离法研究了SiC纳米片的尺寸对SiC铁磁性的影响和调控，结合各项测试数据分析，得出SiC纳米片的铁磁性来源于表面缺陷，并且可以通过控制纳米片的尺寸进而调控SiC材料的铁磁性。其次，采用高能球磨法成功制备出纯相SiC纳米颗粒，并对其结构、形貌、光学和磁学特性进行了系统研究。结合光学性质及电子自旋共振谱的研究，表明其铁磁性与材料表面缺陷相关。进而我们还将材料拓展到另一宽带隙稀磁半导体材料氮化硼（BN），研究了BN纳米片的尺寸、结晶度、缺陷对铁磁性的调控，结合第一性原理计算，得出BN纳米片铁磁性的磁矩主要来源于N空位周围最近邻和次近邻的B原子。以上工作为实现稀磁半导体材料在自旋电子学中的应用提供理论依据和实验基础。.作为本项目的研究扩展，我们还研究了尖晶石氧化物CoFe2O4的铁磁性。并将尖晶石材料（CoFe2O4和Co3O4）应用到能源转化方面，进一步开拓了我们的研究方向及思路。申请人及项目组参与者在此基金项目的资助下共发表已标注基金项目批准号的SCI论文9篇，项目负责人培养硕士毕业生1人，在读硕士研究生3人。