硬磁性大块非晶合金晶化过程中铁磁交换耦合作用和畴壁钉扎作用的研究

硬磁性大块非晶合金的独特矫顽力机理引人关注，本项目将以RE-Fe-(Co)-M(RE=Nd, Pr, M=Al, Si)系大块非晶合金为研究对象，以合金在晶化过程中的铁磁交换耦合作用与畴壁钉扎作用的变化为切入点，研究这两种作用机制对合金矫顽力的贡献，分析该类合金的矫顽力机理。利用高分辨透射电镜和三维原子探针技术分析镶嵌在非晶基体上的纳米晶（或纳米团簇）的成分、结构、尺寸和分布的变化规律。通过分析磁交互作用曲线和磁畴结构的相应变化，研究铸态非晶合金及其在晶化过程中的铁磁交换耦合的作用机制。分析铸态非晶合金及其在晶化过程中矫顽力随温度的变化规律，利用磁粘滞行为的研究计算相应合金的钉扎力，研究合金的畴壁钉扎机制。建立合金的微观结构与宏观磁性能之间的实验和理论关系，进而阐明其矫顽力机理。该项目的研究不仅可以补充完善非晶磁学理论，而且对于该类合金最终走向实际应用有着重要的意义。

The bulk amorphous alloys with hard magnetic behavior have attracted considerable attention due to the unique coercivity mechanism. On the basis of changes between magnetic exchange coupling effect and the role of strong pinning of domain walls, the coercivity mechanism of RE-Fe-(Co)-M(RE=Nd, Pr, M=Al, Si) bulk amorphous alloys will be investigated in this project. The composition, microstructure, size and distribution of nanocrystals embedded in the amorphous matrix will be explored by using high resolution transmission electron microscope and three dimentionalatom probe. Furthermore, the magnetic exchange coupling effect of as-cast samples and its changes during crystallization process will be investigated by analyzing the corresponding changes of exchange coupling curves and domain wall structures. The temperature dependence of the coercivity in as-cast samples and samples annealed at different temperatures will be studied. Also, the value of maximum pinning force will be calculated from key parameters of magnetic viscosity to better understand the effect of strong pinning of domain walls. The correlation of microstructure and magnetic properties will be explored to gain a deeper insight into the coercivity mechanism in RE-Fe-(Co)-M (RE=Nd, Pr, M=Al, Si) bulk amorphous alloys. This investigation will not only give a supplement to magnetic theory of amorphous alloys, but also have important meaning to trigger their applications.