铁系纳米材料的微结构和电磁输运机理研究

Studies show that electromagnetic transport properties of ferric nanomaterials are significantly affected by grain boundaries, microstructures and decreased scales or dimensions. When system size of the material is close to characteristic length related to transport properties, special electrical and magnetic behaviors usually appear, which attracts much attention recently. However, further research is still required on the physical mechanism of such electromagnetic transport. In this project, ferric nanomaterials with controlled size and shape, such as FePt, CoPt, Fe2O3, are prepared by physical and chemical methods, and complex nanostructure assembling systems are constructed through material design and controllable synthesis. Unique features of microstructure and electromagnetic properties under this nanoscale compared with simple particle system or traditional block materials will be investigated, and the effect of preparation, composition, scale, dimension, grain boundary, microstructure, temperature, electric field and magnetic field on the electromagnetic transport properties will be systematically studied. The above experimental exploration, combining with physical model verification, will reveal the intrinsic electromagnetic transport mechanism of these ferric nanomaterials. Related research results can enrich the transport theories of nanomaterial system and provide basis for the preparation and application of ferric nanomaterials.

研究表明，铁系纳米材料的颗粒边界、微结构，尺度和维度的减小对其电磁输运性能影响显著。与输运性质相关联的特征物理长度通常处于纳米量级，当材料体系尺寸与相关特征物理长度相近时，则呈现出新颖的电学和磁学行为。该领域近年来受到广泛关注，而电磁输运的物理机制有待进一步研究。本项目利用物理和化学方法制备尺寸和形状可控的铁系（如FePt，CoPt，Fe3O4等）纳米材料，并通过材料设计、可控合成构建复杂结构的铁系纳米组装体系；寻找纳米尺度样品的微结构和电磁性能区别于简单纳米粒子体系和块体材料的特征；系统研究成分、尺度、维度、颗粒边界、晶粒织构、温度、电场和磁场对其电磁输运性能的影响，探索铁系纳米材料的电磁输运规律，结合物理模型的构建与验证揭示其内禀电磁输运机制。研究结果将进一步丰富低维材料体系的输运理论，为铁系纳米材料的可控制备和应用提供依据。

铁系纳米材料的尺度，维度和微结构对其电磁输运性能影响显著，进一步探索其影响规律，揭示电磁输运的物理机制具有重要的学术价值和潜在的应用价值。本项目利用物理和化学方法制备不同维度的铁系纳米材料（如Fe、FePt、Fe3O4等）样品，通过材料设计和参数调控，实现了体系尺寸和形状的可控制备；研究了尺寸，形貌，颗粒边界，温度，电场，磁场，制备条件等对铁系纳米材料电磁输运性能的影响。在准二维纳米薄膜体系中，分别研究了FePt合金薄膜，Fe/Si单晶薄膜，Ni/PMN-PT薄膜的电学性质和输运性质，发现了影响其性质的关键因素。在准零维纳米颗粒体系中，着重研究了Fe3O4纳米颗粒体系的低场输运性质，得到了退火温度对其微结构，磁性和电磁输运性质的影响规律。. 通过构筑复杂结构铁系纳米粒子组装体系，明确了材料制备、成分、微结构和电磁学性能之间的内在联系，进一步揭示了纳米尺度铁系材料的电磁输运机理。这些研究结果进一步丰富了低维材料体系的输运理论，为铁系纳米材料的可控制备和应用提供基础支撑。