Identifying grain boundary and intragranular pinning centres in Sm2(Co,Fe,Cu,Zr)17 permanent magnets to guide performance optimisation
Abstract
Permanent magnets draw their properties from a complex interplay of chemical composition and phase, each with their associated intrinsic magnetic properties. Gaining an understanding of these interactions is the key to deciphering the origins of a permanent magnets' magnetic performance and facilitate the engineering of much improved-performing magnets. Here, we use advanced multiscale microscopy and microanalysis on a bulk Sm2(Co,Fe,Cu,Zr)17 pinning-type high-performance magnet with outstanding thermal and chemical stability. Comparison of the microstructure in regions of different composition, we demonstrate that the pinning of magnetic domains, imaged by nanoscale magnetic induction mapping, is controlled by the composition and atomic arrangement of copper. This is confirmed by micromagnetic simulations. Contrary to the belief that grain boundaries are "weak links" in magnetic materials, we demonstrate grain boundaries undergo magnetization reversal at relatively low fields (0.1-0.3 T), but this remains confined to these regions and does not significantly impact the magnet's coercivity. Our results showcase that it is the optimal microstructure within the grain itself that is crucial for achieving the desired magnetic properties.
Keywords
Cite
@article{arxiv.2304.14958,
title = {Identifying grain boundary and intragranular pinning centres in Sm2(Co,Fe,Cu,Zr)17 permanent magnets to guide performance optimisation},
author = {Stefan Giron and Nikita Polin and Esmaeil Adabifiroozjaei and Yangyiwei Yang and Fernando Maccari and András Kovács and Trevor P. Almeida and Dominik Ohmer and Kaan Üstüner and Alaukik Saxena and Matthias Katter and Iliya A. Radulov and Christoph Freysoldt and Rafal E. Dunin-Borkowski and Michael Farle and Karsten Durst and Hongbin Zhang and Lambert Alff and Katharina Ollefs and Bai-Xiang Xu and Oliver Gutfleisch and Leopoldo Molina-Luna and Baptiste Gault and Konstantin P. Skokov},
journal= {arXiv preprint arXiv:2304.14958},
year = {2025}
}