Nd-Fe-B/α-Fe基纳米复合多层膜的界面析出及其交换耦合的研究

软磁相与硬磁相之间的界面微结构影响两相之间的交换耦合，从而决定纳米复合磁体的磁性能。本项目以Nd-Fe-B（硬磁相）/α-Fe（软磁相）基纳米复合磁性多层膜为研究对象，利用硬磁相/软磁相层界面含大量原子空位、位错等结构缺陷易成为析出相形核核心的优势，首先调控α-Fe软磁层溅射靶材成份，溅射含Nd、Cu、Nb或Si的Fe（Nd）、Fe（Cu）、Fe（Nb）及Fe（Si）过饱和固溶体软磁层，再优化溅射后续退火处理工艺，促使过饱和固溶体软磁层中过饱和元素或其化合物在界面析出，从而修饰和调控磁性层之间的界面微观结构。使用透射电子显微镜、电子能量损失谱等技术表征复合薄膜磁性层界面的微结构演变过程，归纳不同过饱和元素或其化合物在界面处的析出规律。通过磁性测量分析软磁层和硬磁层之间的交换耦合行为及交换耦合作用随界面微结构演变的规律，获得提高纳米复合磁性多层膜磁性能的最佳界面析出工艺，归纳其物理机理。

The interfacial microstructures between soft and hard magnetic phases decide the magnetic properties of nanocomposite magnets through affecting the exchange coupling. In this project, the Nd-Fe-B (hard magnetic phase)/α-Fe (soft magnetic phase) based nanocomposite magnetic film will be investigated. Because of the existence of lots of voids and dislocation microstructural defects, the interfaces between hard magnetic and soft magnetic phases could become the nucleation sites of the precipitates. These interfacial structural features will be made good use of. The super-saturated Fe-based solid solutions with the solutes (Nd, Cu, Nb or Si) will be prepared by magnetron sputtering through changing the target compositions. The supersaturated solutes or their compounds will precipitate at the interfaces during the heat treatment of sputtered thin films to modify the interfacial microstructures. The detailed evolution of the interfacial structures, atomic diffusion of supersaturated solutes will be carefully characterized by using electron transimission microscopy (TEM), electron energy loss spectroscopy (EELs). The exchange coupling and its change with interfacial microstructures will be clarified using magnetic measurements. A intrinsic relationhsip between exchange coupling and interfacial microstructures will be obtained. An optimum technique of interfacial precipitation will be achieved to improve the magnetic properties of nanocomposite multilayered magnetic films and its physical mechanism will be revealed.