The Effect of Long-range Dumbbell Ordering on the Properties and Microstructures of Rare Earth Permanent Magnets

这项研究探索了基于CaCu5型结构导数的稀土永磁系统的过渡金属哑铃浓度、有序性、微结构和磁行为之间的相互关系。主要目的是研究Sm-Co、Pr-Co和Sm-Fe中无序的TbCu7型结构和有序的Th2Zn17型结构之间的转变。研究了过渡金属哑铃的浓度和构型，包括长程有序度和有序化方式对微结构/磁性能关系的影响。此外，还将研究总体微结构对磁体反转机制的影响，这些磁体被设计为具有从纳米到微米的颗粒结构。该项目的一个目标是开发磁性计量技术，将磁性行为与微结构特征联系起来。最终，这些结果将提供从亚纳米到微米的长度范围内稀土永磁体中各种原子结构/微结构/磁性能关系的细节。%稀土永磁体是技术进步不可或缺的一部分。设备的进一步小型化、更多的电动汽车、更节能的电机以及改进的医学成像技术，都需要在苛刻的环境中具有更高能量密度和更高性能的永磁体。全面了解结构和性能之间的相互关系以及磁化反转过程对于开发先进的永磁体技术至关重要。更广泛的影响包括研究生和本科生的教学和培训，科学和工程领域代表性不足的群体的参与，以及通过使用布鲁克海文、阿贡和橡树岭国家实验室的设施发展基础设施。

This grant explores the interrelationship between transition metal dumbbell concentration, ordering, microstructure, and magnetic behavior of rare earth permanent magnet systems based on structural derivatives of the CaCu5-type structure. A major objective is to investigate various aspects associated with transformations between the disordered TbCu7-type and ordered Th2Zn17-type structures in Sm-Co, Pr-Co and Sm-Fe. The influences of the transition metal dumbbell concentration and configuration, including the degree of long-range order and the order pattern will be studied on the microstructure/magnetic properties relationship. In addition, the effect of the overall microstructure will be investigated on the reversal mechanism in magnets designed to have grain structures ranging from the nanoscale to the microscale. A goal of the project is to develop magnetic metrology techniques to tie the magnetic behavior to microstructural features. Ultimately, the results will provide details of the various atomic structure/microstructure/magnetic property relationships in rare earth permanent magnets over length scales ranging from sub-nanometer to micrometer.%%%Rare earth permanent magnets are integral to technological advancements. Further miniaturization of devices, more electric vehicles, more energy-efficient motors, and improved medical imaging technology all require permanent magnets with higher energy densities and improved performance in demanding environments. A complete understanding of the interrelationships between structure and properties and an understanding of the magnetization reversal process are critical to developing advanced permanent magnet technology. Broader impacts include teaching and training of graduate and undergraduate students, involvement of underrepresented groups in science and engineering, and development of infrastructure through use of facilities at Brookhaven, Argonne and Oak Ridge National Laboratories.***