Fe-M单晶薄膜的磁化反转行为研究

The study about the magnetization reversal mechanism of iron-based magnetic thin films has not yet formed a consistent conclusion, there are problems to be solved. In this proposal, Fe-M（M：Co, Pt, Ga）monocrystalline films with simple structure and easy to construct the physical model choosed as the object, the magnetization reversal behaviors and modulation of magnetization reversal process will be systematically investigated. The magnetization reversal mechanism of Fe-M（M：Co, Pt, Ga）monocrystalline films will be revealed which have both the academic value and the potential value of applications. In this study, the Fe-M（M：Co, Pt, Ga）monocrystalline films will be physically deposited under ultrahigh vacuum, and the effects of such different components and substrates on magnetics and transport properties will be investigated. Through the multi-field coupling (e.g. magnetic filed, electric field or force field) and the modulation of the composition and growth mode of the films, the interactions between Fe and M, and electronic states of the films will be modified, which will induce various magnetization reversal processes and transport phenomena. Based on the above results, the competitive relationship between magneto-crystalline anisotropy and shape anisotropy of these samples will be studied in details; also, the physical mechanisms of above-mentioned behaviors and/or phenomenon changes can be revealed, and the transport properties of iron-based monocrystalline films can be improved. Combined with the theoretical and experimental research, the technical approach of the novel iron-based magnetic monocrystalline films with the multi-field coupling characterization is explored. The research results will enrich both the magnetization reversal mechanism and the low-dimensional magnetic nanostructure theory; also, it will be of value for practical applications.

铁基磁性薄膜的反磁化机制研究尚未形成一致的结论，存在亟待解决的问题。本项目选择晶体结构简单、易于构建物理模型的Fe-M（M：Co, Pt, Ga等）单晶薄膜为载体，开展磁化反转行为和反磁化过程的调控研究，揭示Fe-M单晶薄膜的磁化反转机理，具有重要的学术意义和潜在应用价值。采用超高真空物理沉积技术，生长以铁为基体的二元或多元Fe-M单晶薄膜，研究组分、基底调控等对薄膜磁学性质及输运性质的影响；通过多场耦合以及对薄膜组分、生长方式的调控，使薄膜中Fe-M间互作用、电子态等发生变化，诱导出不同的磁化反转过程及输运现象，进而分析单晶薄膜的磁晶各向异性和形状各向异性之间的竞争关系；揭示产生这些行为/现象变化的物理机制，提升铁基薄膜磁电阻等输运特性；将理论与实验研究相结合，探索制备具有多场耦合特征的新型铁基单晶薄膜的技术途径。研究结果将丰富相关磁化反转机理和低维磁性纳米结构的理论，为实际应用奠定基础。

本项目研究物理内涵丰富的铁基磁性薄膜的反磁化机制。选择晶体结构简单、易于生长的Fe-M单晶薄膜为载体，开展了磁化反转行为和反磁化过程的调控研究，揭示其磁化反转机理。在样品制备方面，采用超高真空物理沉积技术，成功制备了以铁为基体的二元及多元Fe-M单晶薄膜，包括Fe(001)、 FeMgO(001)、Fe/Si(001)薄膜等，研究了组分、基底调控等对薄膜磁学性质及输运性质的影响；在物性测量表征方面，通过多场耦合以及对薄膜组分、生长方式的调控，使薄膜中Fe-M间互作用、电子态等发生变化，诱导出不同的磁化反转过程及输运现象，进而分析了单晶薄膜的磁晶各向异性和形状各向异性之间的竞争关系，揭示了产生这些行为/现象变化的物理机制，从而提升了铁基薄膜磁电阻等输运特性。本项目理论与实验研究相结合，探索了制备具有多场耦合特征的新型铁基单晶薄膜的技术途径。这些研究结果丰富了相关磁化反转机理和低维磁性纳米结构的理论，具有重要的学术意义和潜在应用价值。. 为培育新的研究方向，本项目采用理论和实验方法研究了外尔半金属TaAs的热、电输运性质和三维蜂窝材料的拓扑相变，探索了一维自旋链材料Cu(NO3)2·2.5H2O的磁热力学性质，提出了一种计算量子多体系统有限温度性质的新算法。这些拓展内容的研究也取得重要进展和有价值的结果。