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

University Of Nebraska-Lincoln, Lincoln NE

Investigators

Abstract

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. ***