自支撑LiFe5O8外延薄膜的弯曲磁结构解析与微磁学仿真研究

随着柔性电子市场的不断升级，发展具有高度集成特性、柔韧性与功能性的新型电子材料成为当前柔性电子领域的研究热点。以LiFe5O8为代表的自支撑铁氧体外延薄膜作为一种新兴的柔性软磁介质，其类单晶的有序特性与优秀的大扭曲自由度赋予其丰富的磁电特性和研究前景。故研究其中的弯曲机制尤其是结构物性关系成为当前的热点和难点问题。目前自支撑铁氧体薄膜弯曲磁性调控理论的研究瓶颈在于弯曲机制相对复杂，难以建立起微观机制与表观磁特性之间的关系。而理论上的突破将有可能为新器件开发提供新的设计方向。因此，本项目以LiFe5O8柔性自支撑薄膜为研究对象，旨在通过合理的薄膜设计、精细的结构表征与配套的微磁学仿真实现对柔性薄膜弯曲磁结构的解析与机制的阐述，主要包括：（1）形状对磁性的调控作用；（2）应变场的作用机制；（3）微观缺陷机制。最终归纳总结各机制并得到能够良好预测大多数柔性薄膜弯曲规律的磁结构仿真模型。

With the continuous upgrading of flexible electronic market, it has become a hotspot to develop new electronic materials with high integration, flexibility and functionality. Freestanding ferrite epitaxial thin films, like LiFe5O8, are a type of novel flexible soft magnetic medium which has rich magnetoelectric properties and research prospects due to its single-crystalline-like ordering characteristics and large twist degree of freedom. Therefore, it is not only a hot and but also an emergent problem to study the bending mechanism of freestanding films, especially the relationship between structure and physical properties. The main bottleneck of the magnetic theory in flexible freestanding film is that the bending mechanism is relatively complex, which make it hard to establish the relationship between the micro-mechanism and the macro magnetic performance. The breakthrough in theory may provide a new design direction for the development of new devices. Therefore, this project will take LiFe5O8 freestanding film as the research object. Through properly film design, fine structure characterization and matching micromagnetic simulation, we aim to establish the relationship among magnetic structure, defect mechanism and macro magnetic performance. The research mainly includes: (1) the effect from bending shape on magnetic properties; (2) the mechanism of strain field on film magnetism; (3) the defect mechanism. Finally, we aim to build a proper magnetic structure model which can predict the bending induced magnetic change for most flexible film systems.