面心四方（fct）相FePt纳米颗粒在磁记录介质、永磁体、电化学产氢催化剂、纳米生物医药等领域具有广阔的应用前景。本项目拟采用高分辨率透射电子显微镜同步分析直接合成fct-FePt纳米颗粒的微观结构，从微观结构演化角度阐明通过降低FePt空位形成能促进其低温相变的机制。运用LB膜或嵌段共聚物模版技术，实现fct-FePt纳米颗粒阵列单层膜的大面积自组装。采用几何相位分析方法，解析FePt单层膜应力场分布与取向的内在关系，揭示应力调控其取向的物理机制。采用经典蒙特卡罗模拟并结合第一性原理计算分析自组装FePt纳米颗粒阵列的磁学特性，获得具有优良磁性能的FePt纳米结构，为促进其应用奠定基础。

Face centered tetragonal (fct) phase FePt nanoparticles have wide application prospect in the fields of magnetic recording media, permanent magnet, hydrogen evolution reaction electrocatalyst, and nanometer bio-medicine. This project intends to analyze the microstructure of direct synthesized fct-FePt nanoparticles by high resolution transmission electron microscopy observation, point out the low temperature phase transition mechanism through decreasing of the activation energy for vacancy formation from the perspective of microstructure evolution. fct-FePt nanoparticles array monolayer will be assembled in large area by using LB technique or Block co-polymer patterns. The inherent relationship between stress field distribution and orientation for FePt monolayer will be investigated by the geometric phase analysis method, to reveal the mechanism of stress modulated orientation for FePt nanoparticles. The magnetic properties of self-assembled FePt nanoparticles array will be also simulated in detail by using the classical Monte Carlo simulation combined with first principles calculation. Through this study, FePt nanostructures with excellent magnetic properties could be yielded to lay the foundation for their potential applications.